Area of parallelograms and triangles: Class 7 practice
Area of a parallelogram = base × height; area of a triangle = ½ × base × height. Read the method, follow the three worked examples, then try the six questions.
What you should know first
- Area of rectangles
The idea behind area of parallelograms and triangles
Area of a parallelogram = base × height; area of a triangle = ½ × base × height. The height must be perpendicular to the chosen base.
Step-by-step method
- Pick a base and its perpendicular height.
- Parallelogram: b × h; triangle: ½ b × h.
- Rearrange to find a missing base or height.
Worked example 1 (Basic)
Find the area of a parallelogram with base 13 cm and height 3 cm.
- A = 13 × 3
- = 39 cm²
- Answer: 39 cm²
Worked example 2 (Standard)
Find the area of a triangle with base 8 cm and height 15 cm.
- A = ½ × 8 × 15
- = 60 cm²
- Answer: 60 cm²
Worked example 3 (Challenge)
A triangle has area 6 cm² and base 4 cm. Find its height.
- h = 2A ÷ b = 12 ÷ 4
- = 3 cm
- Answer: 3 cm
Common mistakes and misconceptions
- Using the slant side as height
- Forgetting the ½ for triangles
Practice questions
- (Basic) Find the area of a parallelogram with base 13 cm and height 19 cm.
- (Basic) Find the area of a parallelogram with base 23 cm and height 9 cm.
- (Standard) Find the area of a triangle with base 29 cm and height 9 cm.
- (Standard) Find the area of a triangle with base 20 cm and height 7 cm.
- (Challenge) A triangle has area 142.5 cm² and base 19 cm. Find its height.
- (Challenge) A triangle has area 247 cm² and base 26 cm. Find its height.
Answer key with full working
- Q1: A = 13 × 19 → = 247 cm² → Answer: 247 cm²
- Q2: A = 23 × 9 → = 207 cm² → Answer: 207 cm²
- Q3: A = ½ × 29 × 9 → = 130.5 cm² → Answer: 130.5 cm²
- Q4: A = ½ × 20 × 7 → = 70 cm² → Answer: 70 cm²
- Q5: h = 2A ÷ b = 285 ÷ 19 → = 15 cm → Answer: 15 cm
- Q6: h = 2A ÷ b = 494 ÷ 26 → = 19 cm → Answer: 19 cm
Syllabus note
This skill is listed under "Perimeter and Area" for Class 7 in the NCERT/CBSE books. ICSE, IGCSE, IB and state boards may teach it in a different chapter or year.
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.
Related practice and notes
Frequently asked questions
Which chapter is area of parallelograms and triangles in?
"Perimeter and Area", Class 7 Maths (NCERT/CBSE). Other boards may place it differently.
How were the answers checked?
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.