Line ABC is a tangent to a circle at point B. If BP = BQ and \(\angle QBC = 72^\circ\), then find the value of \(\angle PBQ\):
36°
36° is correct.
By the alternate segment theorem, the angle between the tangent ABC and the chord BQ equals the angle that chord BQ subtends in the alternate segment, so \(\angle BPQ = \angle QBC = 72^\circ\).
Since BP = BQ, triangle BPQ is isosceles and the angles opposite the equal sides are equal: \(\angle BQP = \angle BPQ = 72^\circ\).
Angle sum in triangle BPQ: \(\angle PBQ = 180^\circ - 72^\circ - 72^\circ = 36^\circ\).
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In the given circle, diameter AB is extended to meet chord CD extended at P. If the lengths of the line segments AP, CP and DP are 12 cm, 8 cm and 6 cm, respectively, what is the length of the radius of the circle?

There are two concentric circles. The radii of the two circles are 100 m and 110 m respectively. A wheel of radius 30 cm rolls on the smaller circle and another wheel rolls on the larger circle. After they have completed one revolution, it is found that the two wheels rolled equal number of times
on their respective axes. What is the radius of the other wheel ?