We know that the area of triangle = 1/2 x base x height
In first row, base = 15 cm and area = 87 cm²
∴ 87 = 1/2 x 15 x height
⇒ height = 87×2/15 11.6 cm
In second row, height = 31.4 mm and area = 1256 mm²
∴ 1256 = 1/2 x base x 31.4
⇒ base = 1256 x 2/31.4 = 80 mm
In third row, base = 22 cm and area = 170.5 cm²
∴ 170.5 = 1/2 x 22 x height
⇒ height = 170.5 x 2/22 = 15.5 cm

Class 7 Maths Chapter 11 Exercise 11.2

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