17. In the diagram, the lengths AD, BD and CD are all equal and the angle BCD is y. What is the size of the angle ABD ? Ans: 90-y
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29. A vertical radio mast is held in position by a wire which is 48m long. The wire is attached to a point 32 metres up the mast. The wire makes an angle (A) with the mast. What is the size of angle (A)? 48.2 degrees