The distance between the centres, of two equal circles each of radius 4 cm is 17 cm. The length of a transverse tangent is:

Answer: Option A

Let the length of a transverse tangent = x

$$\begin{array}{rl}& =\sqrt{a^2-{\left(r_1+r_2\right)}^2}\\ & =\sqrt{289-64}\\ & =\sqrt{225}\\ & =15\text{ cm}\end{array}$$