In the given figure, quad. ABCD is circumscribed, touching the circle at P, Q, R and S. If AP = 5 cm, BC = 7 cm and CS = 3 cm. Then, the length AB = ?
As we know Tangents drawn from an external point are equal]
In the given Figure, we have
AP = AQ = 5 cm
[Tangents from point A] [AP = 5 cm is given]
BQ = BR = x(say)
[Tangents from point B]
CR = CS = 3 cm [∵ CS = 3 cm is given]
[Tangents from point C]
Given,
BC = 7 cm
CR + BR = 7
3 + x = 7 cm
x = 4 cm
Now,
AB = AQ + BQ = 5 + x = 5 + 4 = 9 cm