17. (a) In the given figure, AB is the diameter of a circle with center O and OA = 7 cm. Find the area of the shaded region.   18. (b) Prove that sin Θ tan Θ 1 − cos Θ = 1 + sec Θ.   19. (c) Mr. Ashok has an account in the Central Bank of India. The following entries are from his pass book:- Date Particulars Withdrawals Rs. P. Deposits Rs. P. Balance Rs. P. 01.01.05 B/F -- -- 1200.00 07.01.05 By cash -- 500.00 1700.00 17.01.05 To cheque 400.00 -- 1300.00 10.02.05 By cash -- 800.00 2100.00 25.02.05 To cheque 500.00 -- 1600.00 20.09.05 By cash -- 700.00 2300.00 21.11.05 To cheque 600.00 -- 1700.00 05.12.05 By cash -- 300.00 2000.00 If Mr. Ashok gets Rs. 83.75 as interest at the end of the year where the interest is compounded annually, calculate the rate of interest paid by the bank in his Savings Bank Account on 31st December, 2005.