Question

R 10. The exterior angle ZACD of AABC is 110° and ZA and B are in the ratio 7: 4. Find all the angles of ABC
but in your answer angle A should be 70°, angle B should be 40° and angle C should be 70°​

Answer 1

We know that an exterior angle of a triangle is equal to the sum of its interior opposite angles.

∴ 2x+3x=110o

5x=110

x=110/5=22

∴ ∠A=2x=2=2×22=44o

∠B=3x=3×22=66o

But ∠A+∠B+∠C=180o

44o+66o+∠C=180o

110+∠C=180o

∠C=180−110

∠C=70o

∠A=44o, ∠B=66o, ∠C=70o