From the given information, we have:
PC = 10 (length of segment PC)
∠CBD = x°
∠BCD = x + 54°
We can determine the relationship between angles ∠CBD and ∠BCD by recognizing that they are inscribed angles intercepting the same arc CD. In a circle, the measure of an inscribed angle is half the measure of its intercepted arc. Therefore, we have:
∠BCD = 1/2(arc CD)
Since ∠BCD = x + 54° and arc CD is the diameter, which is 180°, we can set up the following equation:
x + 54 = 1/2(180)
Simplifying the equation:
x + 54 = 90
x = 90 - 54
x = 36
So, the measure of ∠CBD (m∠CBD) is 36°.