Question

Find the Error: A student is finding the measures of the angles in a triangle that have the ratio 4:4:7. Find the mistake and correct it.

4x + 4x + 7x = 180
15x = 180
X = 12

So, the angle measures are 12, 12, and 84.​

Answer 1

84 is the only correct one, the angle measures 12 and 12 should be 48 and 48

Answer 2

angles are 48°, 48°, 84°

Explanation:

ratio of angles = 4 : 4 : 7 = 4x : 4x : 7x ( x is a multiplier )

the sum of the 3 angles = 180 , then

4x + 4x + 7x = 180 , that is

15x = 180 ( divide both sides by 15 )

x = 12

the student made the error of assuming x = 12 was the size of the 2 equal angles.

the correct angles are

4x = 4 × 12 = 48°

4x = 4 × 12 = 48°

7x = 7 × 12 = 84°