Question

given that the lines in figure 10.34 marked with arrows are parallel, determine the sum of the angles A + B + C without measuring.

Answer 1

a + b + c = 180º

Explanation:

Since the lines are parallel, we can trace a line from angle A to angle C, forming a triangle.

Since the sum of all internal angles of a triangle is 180º, and is this question, the internal angles are a,b and c, we have that a + b + c = 180º