Recall that equivalent fractions can be found by multiplying the numerator and

the denominator by the same number.

So, 5:7 = or .

Thus,we can write 5:7:8 as 5x:7x:8x and use those measures for the triangle sides.

In a triangle, sum of the measures of angles is 180.

        (Angle sum theorem)

                       (Combine like terms)

                                (Divide each side by 20)

Use to determine the measures of each angle of the triangle.

5x = 5(9) or 45

7x = 7(9) or 63

8x = 8(9) or 72

The measures of the angles of the triangle are 45, 63, and 72.