Answer:
 the three angle measures are 35°, 29°, 26°
Step-by-step explanation:
The sum of the angle measures will be 90°, assuming the sections do not overlap. Then ...
 ( 7x - 49) + ( 2/3x + 21) + ( 3/4x + 17) = 90
 (8 5/12)x -11 = 90 . . . . . simplify
 x = 101/(8 5/12) = 12 . . . divide by the coefficient of x
Then the angles are ...
 7x -49 = 7·12 -49 = 35
 2/3x + 21 = 2/3·12 +21 = 29
 3/4x +17 = 3/4·12 +17 = 26
The angle measures are 35°, 29°, 26°.
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Check
 35 +29 +26 = 90 . . . . the sum of the covered section angles is 90°
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We assume you can manage addition of fractions and division by a mixed number or improper fraction. If not, convert all of the coefficients of x to multiples of 1/12. Instead of dividing by the coefficient of x, multiply by the inverse of the coefficient of x.
