Answer:
a = 84°
b = 21°
c = 48°
Explanation:
Step 1.)
The first step is recognizing the angle of 75° is sticking out from a straight-line, PQ. That straight-line represents an angle of 180°
180°-75° = 105 = a° + b°
Step 2.)
We also know that the line RS is 180°. Therefore, it must be true that
75° + 4b° + b° = 180°
or simply
5b + 75 = 180°
Now solve for b. Subtract both sides by 75 and divide the right side by 5
5b = 105°
b = 21°
4b° = 4 x b = 4 x 21° = 84° = 4b°
Step 3)
Since we know that a + b = 105°, we use substitution to get:
a + 21° = 105
Now subtract both sides by 21
a = 84°
Now let's double check if a + b + 75 = 180
84 + 21 + 75 = 180 [check]
Step 4.)
Since we know that PQ is a straight-line that is 180°, we can say:
180° = 4b° + 2c°
Now substitute 4b with 84°
180° = 84° + 2c
Now solve by subtracting 84 from 180 and divide by 2, if needed.
96° = 2c°
48° = c°
Now double check
96° + 84° = 180° [check]
Therefore:
a = 84°
b = 21°
c = 48°
Hope that helps.
Don't forget to show some love and award stars!