Question

use the heron formulae to find the area of the triangle whose sides are 13 cm,14 cm and 15 cm.

Answer 1

a = 13 cm

b = 14 cm

c = 15 cm

S = ( 13 + 14 + 15) /2

=> S = 42 / 2

=> S = 21

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

= sqrt [ 21 (21-13) (21-14)(21-15)]

= sqrt ( 21 × 8 × 7 × 6)

= sqrt ( 3 × 7 × 2 × 2 × 2 × 7 × 2 × 3)

= 3 × 7 × 2 × 2

= 84 cm^2

Answer 2

a = 13 cm

b = 14 cm

c = 15 cm

S = ( 13 + 14 + 15) /2

=> S = 42 / 2

=> S = 21

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

= sqrt [ 21 (21-13) (21-14)(21-15)]

= sqrt ( 21 × 8 × 7 × 6)

= sqrt ( 3 × 7 × 2 × 2 × 2 × 7 × 2 × 3)

= 3 × 7 × 2 × 2

= 84 cm^2