Answer:
C) 3x=54
Explanation:
Angle ABD is a straight angle, which means it measures 180 degrees.
Angles ABC & CBD are linear pairs. (The two of them add up to 180°)
ABD is a right angle (90 degrees)
The straight angle (180) minus the right angle (90) equals 90 degrees.
x+2x+2x=90°
Combine like terms
5x=90°
divide by 5 on both sides
x=18
18×3=54
C
Hope this helps :-)