CBSE Class 10 Mathematics (Standard) — Circles

If TP and TQ are two tangents to a circle with centre O from an external point T so that $\angle POQ = 120°$, then ∠ PTQ is equal to : (a) 60° (b) 70° (c) 80° (d) 90°

In the given figure, PA is a tangent from an external point P to a circle with centre O. If $\angle POB = 125°$, then ∠ APO is equal to : (a) 25° (b) 65° (c) 90° (d) 35°

Two concentric circles are of radii 5 cm and 4 cm. Find the length of the chord of the larger circle which touches the smaller circle.

In the given figure, Δ ABC is a right triangle in which $\angle B = 90^\circ$, AB = 4 cm and BC = 3 cm. Find the radius of the circle inscribed in the triangle ABC.

OR In the given figure, if a circle touches the side QR of Δ PQR at S and extended sides PQ and PR at M and N respectively, then prove that : $PM = \frac{1}{2}(PQ + QR + PR)$