Find the curved surface area, in square centimetres, of a hemisphere whose diameter is 28 cm. Use pi = 22/7 unless stated otherwise.

Introduction / Context:
This question tests knowledge of the curved surface area formula for a hemisphere. A hemisphere is half of a sphere, and its curved surface area excludes the flat circular base. The radius is obtained from the given diameter, and then the standard formula for curved surface area is applied. Accurate substitution and simplification are necessary to reach the correct numerical result.

Given Data / Assumptions:

• Diameter of hemisphere = 28 cm.
• Radius r = diameter / 2.
• Curved surface area of a hemisphere = 2 * pi * r^2.
• Use pi = 22/7.

Concept / Approach:
The key formula is curved surface area = 2*pi*r^2. First convert diameter into radius. Then substitute r and pi into the formula. Since pi is given as 22/7, we can simplify neatly using fraction arithmetic. Take care not to include the base area, because the question asks only for the curved surface area, not total surface area.

Step-by-Step Solution:
Diameter = 28 cm, so radius r = 28 / 2 = 14 cm.Curved surface area = 2 * pi * r^2.Substitute values: 2 * (22/7) * 14^2.Compute 14^2 = 196.So area = 2 * (22/7) * 196.Simplify 196 / 7 = 28.Area = 2 * 22 * 28 = 44 * 28.44 * 28 = 1232 sq cm.

Verification / Alternative check:
Another way is to compute in steps: pi*r^2 = (22/7)*196 = 22*28 = 616. Then 2*pi*r^2 = 2*616 = 1232 sq cm. Both sequences confirm the same result, validating the calculation. The answer is well within a sensible range for a hemisphere with radius 14 cm.

Why Other Options Are Wrong:
1152 sq cm and 1024 sq cm arise from incorrect handling of the fraction 196/7 or wrong multiplication at the end. 956 sq cm and 1344 sq cm result from mixing total surface area and curved surface area formulas or from calculation errors. Only 1232 sq cm fits the correct application of 2*pi*r^2 with the given values.

Common Pitfalls:
Common errors include using the total surface area formula 3*pi*r^2 instead of the curved surface area, forgetting to divide the diameter by 2 to get radius, and miscalculating 196/7 or final products. Always confirm whether the problem asks for curved surface area or total surface area before choosing the formula.

Final Answer:
1232 sq cm