Answer:
B. 7
Step-by-Step-Explanation:
This is a right angle, a right angle is equal to 90° since it is 1/4 of 360
(360 is all the way around)
Our equation here is;
5x° + 55° = 90°
(we do inverse operation, inverse of addition is subtraction.)
Subtract 55° from both sides, 55 - 55 cancels out (0)
90° - 55° = 35°
Now our equation is;
5x° = 35°
(to find x we need to find out what 1x equals so we divide 35° by 5°)
(35 / 5 = 7)
x = 7
To make sure we plug in it into our original equation (5x° + 55° = 90°)
5(7)° + 55° = 90°
35° + 55° = 90°
(35 + 55 = 90 so this is correct)
x = 7