Help isosceles & equilateral

Answer:
100°
Step-by-step explanation:
a + b = 140° because the sum of two interior angles in a triangle is equal to an exterior angle
Since this triangle is isosceles, which means QP = QR we can find the value of b as 40° because its supplementary to 140° that means the value of a = 140 - 40 = 100°
Answer:
a = 100°
Step-by-step explanation:
This is an isosceles triangle, so angle b = angle c:
140° is an angle outside the triangle. We need the angle in the triangle:
180 - 140 = 40°
angle b = 40°
Total sum of angles in a triangle: 180°
180° = a + b + c
Find a:
= a + 40° + 40°
a = 180° - 80°
a = 100°