Question

Draw a circle of radius $5cm$. From a point $13cm$ away from its centre, construct the pair of tangents to the circle and measure their length. Also verify the measurement by actual calculation.

Answer 1

Step 1 : Draw a circle of radius $5cm$ with centre $O$ using compass

Step 2 : Using ruler draw a line segment $OA$ of length $13cm$

Step 3 ; join $A$ to any point of circle so that the line $AB$ touches the circle.

Step 4 : Measure the length $AB$

${AB}^2+{OB}^2={OA}^2{AB}^2+5^2={\left(13\right)}^2{AB}^2=169-25{AB}^2=144\Rightarrow AB=12cm$

Hence verified