Question

In ΔABC, if a = 18, b = 24, c = 30 then find the values of sin `(A/2)`.

Answer 1

Given:

a = 18, b = 24 and c = 30

∴ 2s = a + b + c

= 18 + 24 + 30

= 72

∴ s = `72/2`

∴ s = 36

`sin  (A/2) = sqrt(((s - b)(s - c))/(bc)`

= `sqrt(((36 - 24)(36 - 30))/((24)(30)`

= `sqrt((12 xx 6)/(24 xx 30)`

= `sqrt(1/10)`

= `1/(sqrt10)`