Question

5. If angle DAC = 30° , find the angles of ∆ABC in the figure 10.23.

Answer 1

angles of ∆ABC are ABC, BCA,CAB.
ABC+BCA+CAB=180
(90-40)+X+(40+30)=180
50+X+70=180
120+X=180
X=180-120
X=60.

therefore 50, 70,60 are the angles.