SOLUTION: In parallelogram ABCD, if the measure of angle A is 5x+30, and the measure of angle D is x, find the measure of angle C.

Algebra ->  Parallelograms -> SOLUTION: In parallelogram ABCD, if the measure of angle A is 5x+30, and the measure of angle D is x, find the measure of angle C.      Log On


   



Question 551331: In parallelogram ABCD, if the measure of angle A is 5x+30, and the measure of angle D is x, find the measure of angle C.
Answer by Theo(13342) About Me  (Show Source):
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angle A is supplementary to angle D (adjacent angles of a parallelogram).
this means that:
5x + 30 + x = 180
combine like terms and subtract 30 from both sides of the equation to get:
6x = 150
divide both sides of the equation by 6 to get:
x = 25
angle C is equal to angle A.
angle A is equal to 5x + 30 = 125 + 30 = 155.
angle C is therefore equal to 155 degrees.
in a parallelogram:
opposite angles are equal.
adjacent angles are supplementary.
this makes angle A equal to angle C and supplementary to B and D which makes angle B equal to angle D.