In the figure below PQR is a tangent to the circle at Q. TS is a diameter and TSR and QUV are straight lines. QS is parallel to TV. Angles SQR = 40° and TQV = 55°.

- Find the following angles giving reasons each case.
- <QTS
- <QRS
- <QVT
- <QUT

- Given that QR = 8cm, and SR = 4cm. Find the radius of the circle.