The graph above shows a circle centred at the origin, O. The point P lies on the circle and has coordinates (-12, 16). Line QR is a tangent to the circle passing through the point P.Name: Date:

Answer the following questions:

1) Calculate the distance OP

2) Hence write down the equation of the circle

3) Calculate the equation of the tangent line QR

4) The tangent line cuts the y-axis at point R. Calculate the coordinates of point R

5) Calculate the area of triangle OPR to 1 d.p.

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2) The equation of the circle is 𝑥

3) The equation of the tangent line QR is y={\Large \frac{3}{4}}x+25

4) R = (0, 25)

5) 0.5 x 20 x 15 ≈ 150

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# Answers

1) Using Pythagoras, (OP)^{2}= (-12)

^{2}+ (16)

^{2}=> OP = 20

2) The equation of the circle is 𝑥

^{2}+ 𝑦

^{2}= 400

3) The equation of the tangent line QR is y={\Large \frac{3}{4}}x+25

4) R = (0, 25)

5) 0.5 x 20 x 15 ≈ 150

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