(a)[2]
Complete the following to demonstrate that triangle $ACD$ is similar to triangle $ABT$.
(b)[3]
If the radii of the circles are $7\text{ cm}$ and $3\text{ cm}$, calculate $CD$.
Mathematics 4024 · O Level · Circle theorems I
Circle theorems I — practice question
In the diagram, $A$ and $B$ are the centres of two circles which are tangent at $P$. The line $ACT$ is tangent to the smaller circle at $T$ and cuts the larger circle at $C$. $D$ is the point on $AB$ for which $\angle CDA=90^\circ$.
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This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$\angle TAB = \angle ATB$ (from the tangent-radius theorem)” …
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