Question Detail
Question
To construct a common direct tangent to two unequal circles with radii R (larger) and r (smaller), what is the effective radius used to draw a circle from the center of the larger circle to intersect a semi-circle, as described on page 15?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Page 15, step 4, states: 'Draw a circle centre O with radius R-r to cut semi-circle at B.' This reduced radius is used to find an auxiliary point that helps determine the tangent.
Hint
Look at 'To Construct a Common Tangent to Two UNEqual Circles' on page 15, specifically step 4 and the associated diagram labels.