Two sides of a triangle are 5cm and 9cm long.The ratio of the opposite angles is 1:3.
问题描述：
Two sides of a triangle are 5cm and 9cm long.The ratio of the opposite angles is 1:3.
Determine the angles and the length of the third side of the triangle!
答
三角形的两边是5厘米和9厘米长.该两边相对角度比例为1 : 3.确定第三个三角形的一边所对的角度和长度!设第三变为x,三个角为α,3α,π-4α 由三角面积公式1/2*5x*sin3α=1/2*5*9sin4α=1/2*9*x*sinα5sin3α=9si...