Geometry
Practice MCQsGeometry is an important quantitative aptitude topic that deals with shapes, sizes, angles, lines, triangles, circles, quadrilaterals, area, perimeter, surface area, and volume.
Geometry is an important quantitative aptitude topic that deals with shapes, sizes, angles, lines, triangles, circles, quadrilaterals, area, perimeter, surface area, and volume. It is commonly asked in competitive exams, aptitude tests, school-level mathematics, and entrance exams.
What is Geometry?
Geometry is the branch of mathematics that studies figures and spaces. It includes two-dimensional shapes such as triangles, rectangles, squares, and circles, and three-dimensional solids such as cubes, cuboids, cylinders, cones, and spheres.
In competitive exams, geometry questions usually test your understanding of formulas, properties of shapes, angle relations, and diagram-based reasoning.
| Concept | Meaning | Example |
|---|---|---|
| Perimeter | Total boundary length of a 2D shape | Fence around a field |
| Area | Space covered by a 2D shape | Floor area of a room |
| Surface Area | Total outer area of a 3D solid | Painting a box |
| Volume | Space occupied by a 3D solid | Water inside a tank |
“Geometry becomes easy when the shape is identified correctly and the formula is applied carefully.”
Key points
- Identify whether the figure is 2D or 3D.
- Use perimeter for boundary length.
- Use area for flat surface measurement.
- Use volume for space inside a solid.
- Angle properties are very important in triangles.
- Always keep units consistent.
Basic Geometry Diagrams
The following diagrams show commonly used shapes in geometry questions.
Triangle
Area of a triangle depends on base and height.
Circle
Area of a circle depends on its radius.
Rectangle
Area of a rectangle is length multiplied by breadth.
Cube
Volume of a cube depends on the cube of its side.
Important Geometry Formulas
Square
Here, \(a\) is the side of the square.
Rectangle
Here, \(l\) is length and \(b\) is breadth.
Triangle
The sum of angles in a triangle is \(180^\circ\).
Circle
Here, \(r\) is the radius.
Cube
All edges of a cube are equal.
Cuboid
Here, \(l\), \(b\), and \(h\) are length, breadth, and height.
Cylinder
Cylinder has circular base and height.
Sphere
Here, \(r\) is the radius of the sphere.
Common Types of Geometry Questions
Area-Based Questions
Find the area of 2D figures.
- Square
- Rectangle
- Triangle
- Circle
Perimeter-Based Questions
Find total boundary length.
- Square perimeter
- Rectangle perimeter
- Triangle perimeter
- Circle circumference
Angle-Based Questions
Use angle properties.
- Triangle angles
- Straight angle
- Complementary angles
- Supplementary angles
Volume Questions
Find space occupied by solids.
- Cube
- Cuboid
- Cylinder
- Sphere
Geometry Method Bank
Multiply length and breadth.
Use radius, not diameter.
Useful in angle problems.
Side multiplied three times.
Tip: In circle questions, if diameter is given, first find radius using \(r = \frac{d}{2}\).
Cylinder Diagram
Step-by-Step Solving Method
| Step | Action | Example |
|---|---|---|
| Step 1 | Identify the shape. | Rectangle, circle, triangle, cube, or cylinder. |
| Step 2 | Write the given values. | Length = 12 cm, breadth = 5 cm. |
| Step 3 | Select the correct formula. | \(A = l \times b\) |
| Step 4 | Substitute values carefully. | \(A = 12 \times 5\) |
| Step 5 | Write answer with correct unit. | \(A = 60 \text{ cm}^2\) |
Solved Examples
| Question | Method | Answer |
|---|---|---|
| Find the area of a rectangle with length 12 cm and breadth 5 cm. |
\[
A = l \times b
\]
\[
A = 12 \times 5 = 60
\]
|
60 cm² |
| Find the perimeter of a square with side 8 cm. |
\[
P = 4a
\]
\[
P = 4 \times 8 = 32
\]
|
32 cm |
| Find the area of a triangle with base 10 cm and height 6 cm. |
\[
A = \frac{1}{2}bh
\]
\[
A = \frac{1}{2} \times 10 \times 6 = 30
\]
|
30 cm² |
| Find the area of a circle with radius 7 cm. Use \(\pi = \frac{22}{7}\). |
\[
A = \pi r^2
\]
\[
A = \frac{22}{7} \times 7 \times 7 = 154
\]
|
154 cm² |
| Find the volume of a cube with side 5 cm. |
\[
V = a^3
\]
\[
V = 5^3 = 125
\]
|
125 cm³ |
| Find the volume of a cuboid with length 8 cm, breadth 4 cm, and height 3 cm. |
\[
V = lbh
\]
\[
V = 8 \times 4 \times 3 = 96
\]
|
96 cm³ |
| Find the missing angle of a triangle if two angles are \(50^\circ\) and \(70^\circ\). |
\[
A+B+C = 180^\circ
\]
\[
C = 180^\circ - 50^\circ - 70^\circ = 60^\circ
\]
|
60° |
| Find the volume of a cylinder with radius 7 cm and height 10 cm. Use \(\pi = \frac{22}{7}\). |
\[
V = \pi r^2h
\]
\[
V = \frac{22}{7} \times 7 \times 7 \times 10 = 1540
\]
|
1540 cm³ |
Note: Always check whether the question asks for perimeter, area, surface area, or volume.
Common Traps and Shortcuts
Common Traps
- Using diameter instead of radius in circle formulas.
- Writing area units instead of volume units.
- Confusing perimeter with area.
- Forgetting the factor \(\frac{1}{2}\) in triangle area.
- Using wrong formula for curved surface area and total surface area.
- Ignoring unit conversion before calculation.
Useful Shortcuts
- If diameter is given, use \(r = \frac{d}{2}\).
- Area uses square units.
- Volume uses cubic units.
- For rectangle, area is \(l \times b\).
- For cube, volume is side cubed.
- Triangle angle sum is always \(180^\circ\).
Practice
A) Multiple Choice Questions
-
Find the area of a square with side 9 cm.
72 cm² 81 cm² 90 cm² 99 cm²
-
Find the perimeter of a rectangle with length 10 cm and breadth 6 cm.
16 cm 26 cm 32 cm 60 cm
-
Find the area of a triangle with base 12 cm and height 8 cm.
36 cm² 48 cm² 60 cm² 96 cm²
-
Find the volume of a cube with side 4 cm.
16 cm³ 48 cm³ 64 cm³ 80 cm³
-
Two angles of a triangle are \(65^\circ\) and \(45^\circ\). Find the third angle.
60° 70° 80° 90°
B) Solve the Higher-Order Problems
- Find the area of a circle with radius 14 cm. Use \(\pi = \frac{22}{7}\). (Hint: \(A = \pi r^2\).)
- Find the volume of a cuboid with length 12 cm, breadth 5 cm, and height 4 cm. (Hint: \(V = lbh\).)
- A rectangle has area 96 cm² and length 12 cm. Find its breadth. (Hint: \(A = l \times b\).)
- Find the curved surface area of a cylinder with radius 7 cm and height 20 cm. Use \(\pi = \frac{22}{7}\). (Hint: \(CSA = 2\pi rh\).)
- The perimeter of a square is 48 cm. Find its area. (Hint: First find side using \(P = 4a\).)
C) Match the Shape with the Correct Formula
| Shape / Concept | Correct Formula |
|---|---|
| Square Area | \(A = a^2\) |
| Rectangle Area | \(A = l \times b\) |
| Triangle Area | \(A = \frac{1}{2}bh\) |
| Circle Area | \(A = \pi r^2\) |
| Cube Volume | \(V = a^3\) |
| Cylinder Volume | \(V = \pi r^2h\) |
Geometry Reminder
Geometry questions become simple when the figure is identified correctly. Always decide whether the question asks for perimeter, area, surface area, volume, or angle. Use the correct formula and write the answer with proper units.
Task: Create five geometry questions using square, rectangle, triangle, circle, and cylinder formulas.
Show Suggested Answers
Multiple Choice
-
81 cm²
\[ A = a^2 = 9^2 = 81 \] -
32 cm
\[ P = 2(l+b) = 2(10+6) = 32 \] -
48 cm²
\[ A = \frac{1}{2} \times 12 \times 8 = 48 \] -
64 cm³
\[ V = a^3 = 4^3 = 64 \] -
70°
\[ \text{Third Angle} = 180^\circ - 65^\circ - 45^\circ = 70^\circ \]
Higher-Order Problems
-
Circle radius \(r = 14\) cm:
\[ A = \frac{22}{7} \times 14 \times 14 = 616 \]Answer = 616 cm².
-
Cuboid dimensions: \(l = 12\), \(b = 5\), \(h = 4\):
\[ V = lbh = 12 \times 5 \times 4 = 240 \]Answer = 240 cm³.
-
Rectangle area \(A = 96\), length \(l = 12\):
\[ b = \frac{A}{l} = \frac{96}{12} = 8 \]Answer = 8 cm.
-
Cylinder radius \(r = 7\), height \(h = 20\):
\[ CSA = 2 \times \frac{22}{7} \times 7 \times 20 = 880 \]Answer = 880 cm².
-
Perimeter of square \(P = 48\):
\[ a = \frac{48}{4} = 12 \]\[ A = a^2 = 12^2 = 144 \]Answer = 144 cm².
Concept Matching
- Square Area → \(A = a^2\)
- Rectangle Area → \(A = l \times b\)
- Triangle Area → \(A = \frac{1}{2}bh\)
- Circle Area → \(A = \pi r^2\)
- Cube Volume → \(V = a^3\)
- Cylinder Volume → \(V = \pi r^2h\)
Clue Explanation
Geometry requires formula selection based on the shape and the quantity asked. Perimeter is boundary, area is surface covered, and volume is space occupied.
Exam tips
- Draw a rough diagram if needed.
- Check whether radius or diameter is given.
- Use square units for area.
- Use cubic units for volume.
- Remember triangle angle sum is \(180^\circ\).
- Do not confuse CSA and TSA.