Answer:
a) isoceles
b) 40°
Step-by-step explanation:
a) an isoceles triangle has 2 sides of equal length
b) Two interior angles of an isoceles triangle are equal.
Also, the sum of the interiors angles of any triangle = 180°
We are told that one of the angles measures 100°. This angle cannot be one of the 2 equal angles, as 2 x 100° = 200° which is greater than the sum of all three angles.
Therefore, the sum of the 2 equal angles must be 180 - 100 = 80
Therefore, the size of one of them = 80 ÷ 2 = 40°
