The angles of a triangle are in the ratio 1:9:8. Find the measurement of the largest of three angles of triangle.  Pick one:
A) 90° B) 100° C) 120° D) 140° E) 160°
If the ratio of the three angles is 1:9:8, then the measures of these angles can be written as x, 9x and 8x. Also the sum of the three interior angles of a triangle is equal to 180°. Hence   x + 9x + 8x = 180   Solve for x   18x = 180   x = 10   The measures of the three angles are   x = 10°   9x = 9 × 10 = 90°   8x = 8 × 10 = 80°   90°
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The angles of a triangle are in the ratio 1:9:8. Find the measurement of the largest of three angles of triangle.