Correct Answer: C

Rationale: The metric system is based on powers of 10, making calculations and conversions easier because each unit increases or decreases by a factor of 10.

Correct Answer: B

Rationale: To find the volume of the triangular shelf, first calculate the area of the triangle (1/2 * base * height) which is (1/2 * 40 * 30) = 600 sq cm. Then, multiply this area by the depth of the shelf (600 * 25) = 15000 cu cm. Therefore, the volume of each shelf is 3750 cu cm. Choice A, C, and D are incorrect as they do not correctly calculate the volume based on the dimensions provided.

Correct Answer: A

Rationale: To find the product of 375 and 2.3, multiply them: 375 2.3 = 862.5. When multiplying by 2.3, it is important to shift the decimal point appropriately after performing the calculation. Choice A, 862.5, is the correct answer. Choice B, 750, is incorrect because it is the result of multiplying 375 by 2. Choice C, 225.75, is incorrect as it appears to be the result of multiplying the numbers in the wrong order. Choice D, 1125, is incorrect as it seems to be the result of multiplying 375 by 3 instead of 2.3.

Correct Answer: D

Rationale: To find the total perimeter, we first calculate the perimeter of the semicircle, which is half of a full circle, so the formula is π * radius. For the semicircle with a radius of 2m, the perimeter is approximately 3.14 * 2m = 6.28m. Next, we calculate the perimeter of the rectangular section by adding twice the length and twice the width (2 * length + 2 * width). For the rectangle with dimensions 5m by 3m, the perimeter is 2 * 5m + 2 * 3m = 10m + 6m = 16m. Finally, we sum the perimeters of the semicircle and the rectangle to get the total perimeter: 6.28m + 16m = 22.28m. Rounding to the nearest meter, the total perimeter is approximately 22m. Therefore, the correct answer is 22m. Choices A, B, and C are incorrect as they do not accurately calculate the total perimeter of the playground fence.

Correct Answer: B

Rationale: The Roman numeral XVII represents the number 17. In Roman numerals, X stands for 10 and V stands for 5. When V (5) is subtracted from X (10), it results in 5 being subtracted from 10, which equals 5. Adding this to V (5) gives the total value of XVII as 17. Choice A is incorrect because it is not the correct numerical value of XVII. Choice C and D are also incorrect as they do not correspond to the Roman numeral XVII.