3.

 In the diagram, the circle has centre O and radius 6 cm. AOC and AED are

 secants of the circle where B, C, D and E are points on the circumference of the

 circle. Given that AC = 16 cm, AD = 14 cm, and ,

(a) find  (b) find the length of AE,  (c) find the length of EB.

4.

 In the diagram, the tangent at B meets AD produced at C. By using similar triangles,

 

 prove that

 Hence, show that