Shown below is a circle with centre O and radius 5 units. PM and PN are tangents and the length of chord MN is 6 units.

Find the length of (PM + PN). Show your work.

 

 In the figure given below, PA is a tangent to the circle with centre O and PCB is a straight line.

Find the measure of $\angle \mathrm{OBC}$. Show your steps and give valid reasons.

ABCD is a square. CD is a tangent to the circle with centre O as shown in the figure below.

If OD = CE, what is the ratio of the area of the circle and the area of the square? Show your steps and give valid reasons.

Shown below is a circle with centre $\mathrm{O}$ and tangents $\mathrm{PQ}$ and $\mathrm{PR}$.

Using triangles $\mathrm{QOR}$ and $\mathrm{PQR}$, and without doing any extra constructions, prove that the tangents $\mathrm{PQ}$ and $\mathrm{PR}$ are equal in length.

In the following figure, $\mathrm{O}$ is the centre of the circle and $\mathrm{PQ}$ and $\mathrm{PS}$ are tangents to the circle at points $\mathrm{Q}$ and $\mathrm{S}$ respectively.

What is the measure of $\angle \mathrm{QRS}$? (Without symbol) Show your work.

A circle has a centre $\mathrm{O}$ and radii $\mathrm{OQ}$ and $\mathrm{OR}$. Two tangents, $\mathrm{PQ}$ and $\mathrm{PR}$, are drawn from an external point $\mathrm{P}$.

In addition to the above information, which of these must also be known to conclude that the quadrilateral $\mathrm{PQOR}$ is a square?

i) $\mathrm{OQ}$ and $\mathrm{OR}$ are at an angle of $90°$.

ii) The tangents meet at an angle of $90°$.

Raghav drew the following figure on a board where a circle is inscribed in a quadrilateral.

(Note: The figure is not to scale)

Then he wrote the following relationships.

i) $\mathrm{ZW}+\mathrm{WX}=\mathrm{XY}+\mathrm{YZ}$

ii) $\mathrm{ZY}+\mathrm{WX}=\mathrm{ZW}+\mathrm{YX}$

Which of the above relationships is/are DEFINITELY true?

In the figure below, $∆\mathrm{PXY}$ is formed using three tangents to a circle centred at $\mathrm{O}$.

(Note: The figure is not to scale)

Based on the construction, the sum of the tangents $\mathrm{PA}$ and $\mathrm{PB}$ is_____the perimeter of $∆\mathrm{PXY}$.

Here is a circle with centre $O$.

Manu wants to draw a tangent $RS$  to the circle.
What is the number of points at which the line $RS$ will meet the circle?