JAMB Mathematics 2020 Objective — Question 17

Question 17 of 40 from the Joint Admissions and Matriculation Board (JAMB) Mathematics 2020 Objective paper, with the correct answer and a full explanation.

Calculate the area of the shaded part in the diagram.

• A. 441cm^2
• B. 462cm^2
• C. 903cm^2
• D. 21cm^2Correct

Explanation

Area of whole sector = (30/360)x(22/7)x(42)^2 = 462cm^2. Area of triangle AOB = (1/2)(42)^2 sin30 = 441cm^2. Shaded area = 462-441 = 21cm^2.

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