SOLUTION: One angle of a triangle is 20 degrees greater than the first angle. The third angle is twice as large as the first angle. What are the measures of the three angles?

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Question 389298: One angle of a triangle is 20 degrees greater than the first angle. The third angle is twice as large as the first angle. What are the measures of the three angles?
Answer by gotpork1(3) About Me  (Show Source):
You can put this solution on YOUR website!
Since angle A is 20 degrees,

1) Find the third angle (C)

C=2A
C=2%2820%29
C=40
so now we have the third angle, C , which is 40 degrees


since the properties of a triangle tell us that the sum of angles must equal to 180 degrees, we can now solve for the last angle
2) Solve for last angle

A+%2B+B+%2B+C+=+180
%2820%29+%2B+B+%2B+%2840%29+=+180
B+=+180+-+20+-+40
B=120
so the 3 angles of the triangle are 20, 40, and 120 degrees