CBSE 10th Class Mathematics
Past year question paper
Year 2020
SET 1, Code Number – 30/2/1
Question Number – 10
Tangent and circle relation
Pythagoras rule
Deepak BoraNewbie
In the given figure, from an external point P, two tangents PQ and PR are drawn to a circle of radius 4 cm with Centre O. If ∠QPR = 90° , then length of PQ is
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Looking to the figure, we can understand that OQ is perpendicular to QP,
Similarly, OR is perpendicular to PR.
consider the tangents PQ and PR, we get,
PQ = PR……..(tangent from a same point that is P)
AC = BC = 4 cm ………..(radius of the circle)
By considering all the above points, we can prove it that it is a square
So, PQOR is a square.
So since it is a square, so all the sides are same,
OQ = OR = RP = QP
∴ QP = 4 cm