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PA and PB are tangents to the circle and O is the centre of the circle. The radius is 5 cm and PO is 13 cm. If the area of the triangle PAB is M, then the value of $$\sqrt \frac {M}{15}$$ is:
In $$\triangle$$OAP,
OA$$^2$$ + AP$$^2$$ = OP$$^2$$
$$=$$> 5$$^2$$ + AP$$^2$$ = 13$$^2$$
$$=$$> 25 + AP$$^2$$ = 169
$$=$$> AP$$^2$$ = 144
$$=$$> AP = 12 cm
Similarly, BP = 12 cm
In $$\triangle$$OAP,
$$\sin x=\frac{OA}{OP}$$
$$\sin x=\frac{5}{13}$$
$$\cos x=\frac{AP}{OP}$$
$$\cos x=\frac{12}{13}$$
In $$\triangle$$ACP,
$$\sin x=\frac{AC}{AP}$$
$$=$$> $$\frac{5}{13}=\frac{AC}{12}$$
$$=$$> AC = $$\frac{60}{13}$$
Similarly, BC = $$\frac{60}{13}$$
$$\cos x=\frac{CP}{AP}$$
$$=$$> $$\frac{12}{13}=\frac{CP}{12}$$
$$=$$> CP = $$\frac{144}{13}$$
Area of the triangle PAB = M
$$=$$> $$\frac{1}{2}$$ x AB x CP = M
$$=$$> $$\frac{1}{2}$$ x (AC+BC) x CP = M
$$=$$> $$\frac{1}{2}\times\left(\frac{60}{13}+\frac{60}{13}\right)\times\frac{144}{13}$$ = M
$$=$$> $$\frac{1}{2}\times\frac{120}{13}\times\frac{144}{13}$$ = M
$$=$$> M = $$\frac{60}{13}\times\frac{144}{13}$$
$$\therefore\ $$ $$\sqrt{\frac{M}{15}}=\sqrt{\frac{60\times144}{169\times15}}=\sqrt{\frac{4\times144}{169}}=\frac{24}{13}$$
Hence, the correct answer is Option B
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