math
posted by hazel on .
the area of a triangle is equal to 48 cm squared and two of its sides measure 12 cm and 9 cm, respectively. find the possible measures of the included angles of the given sides.

A very common formula for the area of a triangle with sides A and B with Ø the contained or included angle between them is
Area = (1/2)(A)(B)sinØ
then
(1/2)(12)(9)sinØ = 48
sinØ = .88888..
Ø = appr 62.7° or 117.3°
make a sketch to see why this is so.
remember:
sinx = sin(180°x)