Two sides of a triangle measure 20 cm and 28 cm. If the area of triangle is 277.13 cm2 how long is the third side in cm?

Answer 1

The area is 1/2 bc sinA so 1/2 20*28 sinA = 277.13
Now, knowing A,
a^2 = b^2 + c^2 - 2bc cosA