Question

Sides of a triangle are cm 45 cm, 39 cm and 42 cm, find its area.

Answer 1

a = 45 cm

b = 39 cm

c = 42 cm

s = `("a" + "b" + "c")/2`

= `(45 + 39 + 42)/2`

s = 63

Area = `sqrt[s (s -a) (s-b) (s - c)]`

= `sqrt[63  (63 -45) (63 - 39) (63 - 42)]`

= `sqrt[63 xx 18 xx 24 xx 21]`

= `sqrt(9 xx 7 xx 9 xx 2 xx 8 xx 3 xx 7 xx 3)`

= `sqrt(9^2 xx 7^2 xx 3^2 xx 16)`

= `sqrt (9^2 xx 7^2 xx 3^2 xx 4^2)`

= `sqrt (9 xx 7 xx 3 xx 4)`       

= 756 cm²