SOLUTION: two angles of a triangle is the same size. the third angle is 12 degrees smaller than the first angle. find the measure the angle

Algebra ->  Angles -> SOLUTION: two angles of a triangle is the same size. the third angle is 12 degrees smaller than the first angle. find the measure the angle       Log On


   

Question 707133: two angles of a triangle is the same size. the third angle is 12 degrees smaller than the first angle. find the measure the angle
Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
The sum of the angles of a triangle equal 180
Equation 1: A+%2B+B+%2B+C+=+180
Equation 2: A+=+B
Equation 3: A+-+12+=+C
------------------------------
Note that equations 2 and 3 are written in terms of A. You can substitute the values of B & C into equation 1.
Equation 1: A+%2B+B+%2B+C+=+180
A+%2B+%28A%29+%2B+%28A+-+12%29+=+180
Combine like terms
3A+-+12+=+180
Add 12 to both sides
3A+=+192
Divide both sides by 3
highlight%28A+=+64%29
------------------------------
Now plug 64 into equation 2 for A
Equation 2: A+=+B
highlight_green%2864+=+B%29
------------------------------
Now plug 64 into equation 3 for A
Equation 3: A+-+12+=+C
64+-+12+=+C
highlight%2852+=+C%29