SOLUTION: One of the equal angles in an isosceles triangle is four times as large as the smalles angle in the triangle. What are the degree measures of the three angles?

Algebra ->  Triangles -> SOLUTION: One of the equal angles in an isosceles triangle is four times as large as the smalles angle in the triangle. What are the degree measures of the three angles?       Log On


   

Question 991870: One of the equal angles in an isosceles triangle is four times as large as the smalles angle in the triangle. What are the degree measures of the three angles?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the sum of the angle of a triangle is 180 degrees.
the angles are x and y.
there are two angles of x degrees and one angle of y.
you get 2x + y = 180
you are given that x = 4y
this means that y = x/4
2x + y = 180 becomes 2x + x/4 = 180
multiply both sides of that equation by 4 to get:
8x + x = 4 * 180
combine like terms to get:
9x = 4 * 180
divide both sides of that equation by 9 to get:
x = 4 * 180 / 9
simplify to get x = 80.
since x is equal to 4 * y, then y = 20.
your 3 angles are 80, 80, 20
they add up to 180.
80 is 4 times 20.
problem is solved.