Question

Find the area of triangle two sides of which are 18 cm and 10cm and perimeter is 42cm

Answer 1

18 + 10+x =42
x=42-28
x=14 cm
area = 1/2 b×h

Answer 2

Let third side be x then
18+10+x=42
28+x=42
x=42-28
x=14
Now,
Semi perimeter=42÷2=21
Area=root under 21(21-18)(21-14)21-10)
=root under 21×3×7×11
=root under(3×7)(3)(7)(11)
=root under3^2×7^2×11
=3×7 root under 11
=21root under 11 cm square
This is the answer root under means you have to kepp those number under root