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Class 9 Measuring Space: Perimeter and Area worksheet
CBSE Mathematics. Area of triangles and quadrilaterals from their sides (Heron's formula). Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The semi-perimeter of a triangle with sides 15 cm, 36 cm and 39 cm is:
- 46 cm
- 90 cm
- 39 cm
- 45 cm
Answer
(d) 45 cm
(15 + 36 + 39) ÷ 2 = 45
- 2.
The area of a triangle with sides 64 cm, 100 cm and 156 cm is:
- 3,840 cm²
- 3,200 cm²
- 1,920 cm²
- 320 cm²
Answer
(c) 1,920 cm²
s = 160; √(s(s − a)(s − b)(s − c)) = 1,920
- 3.
The area of an equilateral triangle of side 20 cm is:
- 100 cm²
- 200√3 cm²
- 60√3 cm²
- 100√3 cm²
Answer
(d) 100√3 cm²
(√3/4) × 20² = 100√3
Section B · short answer
- 4.
Find the area of a triangle with sides 36 cm, 51 cm and 75 cm.
Answer
810 cm²
s = 81; √(81 × 45 × 30 × 6) = 810
- 5.
A rhombus has sides of 20 cm and one diagonal of 24 cm. Find its area.
Answer
384 cm²
the diagonal makes two triangles with sides 20, 20, 24, each 192 cm²
Section C · long answer
- 6.
A triangular park has sides 32 m, 50 m and 78 m. Find its area, and the cost of planting grass at Rs 18 per m².
Answer
480 m²; Rs 8,640
s = 80; area = 480; × 18 = 8,640
Fresh sheets for your child
In the app, every Measuring Space: Perimeter and Area sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.