Question

Q.1: Find the area of a triangle whose two sides are 18 cm and 10 cm and the perimeter is 42cm.
Q.2: The sides of a triangle are in the ratio of 12: 17: 25 and its perimeter is 540cm. Find its area.
Q.3: A field is in the shape of a trapezium whose parallel sides are 25 m and 10 m. The non-parallel sides are 14 m and 13 m. Find the area of the field.
Q.4: A rhombus-shaped field has green grass for 18 cows to graze. If each side of the rhombus is 30 m and its longer diagonal is 48 m, how much area of grass field will each cow be getting?
Q.5: 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.

Answer 1

Answer:

1. Let a, b and c be the sides of triangle.

Perimeter =a+b+c=42 cm

a=18, b=10 

As a+b+c=42

∴ c=42−b−a=42−18−10

∴c=14

Area of triangle = roots(s−a)(s−b)(s−c) 

where, s =a+b+c/2 =21 cm

∴ Area of triangle =root21(21−18)(21−10)(21−14)

∴ Area of triangle =69.69 cm