Practice Questions (Heron’s Formula)
1 What in the area of an equilateral triangle with side 2 cm?
(a) √6cm2 (b) √3cm2 (c) √8cm2 (d) 4cm2
2 What is the length of each side of an equilateral triangle having an area
of
(a) 3cm (b) 4cm (c) 5cm (d) 6cm
3 If the perimeter of an equilateral triangle is 60 cm, then what is its area?
(a) 200√2cm2 (b) 100√2cm2 (c) 100√3cm2 (d) 200√3cm2
4 The sides of a triangle are in the ratio of 3 : 4 : 5. If its perimeter is 36 cm, then
what is its area?
5 The perimeter of a square is (4x+20)cm. What will be the length of its diagonal?
6 Find the area of a triangle having perimeter 32cm. One side of its side is equal to
11cm and difference of the other two is 5cm.
7 Students of a school staged a rally for cleanliness campaign. They walked through
the lanes in two groups. One group walked through the lanes AB, BC and CA;
while the other through AC, CD and DA (see figure). Then they cleaned the area
enclosed within their lanes. If AB = 9 m, BC = 40 m, CD = 15 m, DA = 28 m and LB
= 90�, Which group cleaned more area and by how much? Find the total area
cleaned by the students (neglecting the width of the lanes).
8 Find the cost of laying grass in a triangular field of sides 50 m, 65 m and 65 m at
the rate of Rs 7 per m2 .
