Evaluate:

(i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

(viii)

(ix)

(x)

7

Prove that:

(i)

(ii)

(iii)

(iv)

8

Prove the following:

(i)

(ii)

(iii)

(iv)

(v)

10

In where are acute angles, find the degree measure of .

11

If A, B, C are the interior angles of a , show that:

(i) (ii)