Question

Explain why a + b = d.
B
A
C
swer

Answer 1

Explanation below

Explanation:

Angles in a Triangle

There are two basic relations of angles we need to recall:

• Supplementary angles add up to 180°
• Internal angles of a triangle add up to 180°

Note a, b, and c are the internal angles of the triangle. The angle c is what is needed to a+b to complete 180°, thus:

c = 180 - ( a + b )

Also, note c and d are supplementary angles. Again, c is what is needed to d to complete 180°, thus

c = 180 - d

From the two relations above, it follows that:

a + b = d