How do you find the height of a scalene triangle when given 2 angles and 1 side: side c = 1200, Angle A = 72, Angle B = 77?

1 Answer
Oct 22, 2017

Height h_c = 2159.1276 color (white)(aaa) hc=2159.1276aaawhere h_c hcis height of the triangle with base c = 1200#

Explanation:

Three angles are 72^0, 77^0 & 31^0720,770&310
a / sin A = b / sin B = c / sin CasinA=bsinB=csinC

a / sin 72 = b / sin 77 = 1200 / sin 31asin72=bsin77=1200sin31

:. a = (1200* sin 72) / sin 31 = 2215.8902

b = (1200 * sin 77) / sin 31 = 2270.209

Semi perimeter s = ( a + b + c)/2 = 5686.0991/2 = 2843.0496
s - a = 2843.0496-2215.8902 = 627.1594
s - b = 2843.0496 - 2270.209 = 572.8406
s - c = 2843.0496 - 1200 = 1643.0496

Area of Delta = sqrt(s (s-a) ( s - b) (s - c))

Area = sqrt(2843.0496*627.1594*572.8406*1643.0496)
Area = 1295476.5347

But Area = (1/2) * c * h _c = (1/2) * 1200 * h_c where c is the base.
:. h_c = (1295476.5347* 2) / 1200 = 2159.1276