(a) An angle measures 129º. What is the measure of its supplement?
(b) An angle measures 43°. What is the measure of its complement?
measure of the supplement:
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measure of the complement:

a) Measure of supplement of 129 deg. = 51 deg.

b) Measure of complement of 43 deg. = 47 deg.

Explanation:

a) A pair of supplementary angles is pairs of angles that measure up to 180 deg.

Let the measure of the unknown supplement be 'x'

⇒129+x=180

⇒x=180-129=51.

b) A pair of complement angles is a pair that measure to 90 deg. when added.

Let the unknown angle be 'x'

⇒ 43+x=90

⇒x=90-43=47

yes he does : )