a decorative box has a rectangular base 20cm by 15cm and a hemispherical top with the same diameter as the base what is the total surface area of the

HESI A2

HESI A2 Math Practice

1. A decorative box has a rectangular base (20cm by 15cm) and a hemispherical top with the same diameter as the base. What is the total surface area of the box (excluding the base)?

A. 825 sq cm
B. 1075 sq cm
C. 1325 sq cm
D. 1575 sq cm

Correct answer: C

Rationale: To find the total surface area of the box excluding the base, calculate the lateral surface area of the rectangular base and the surface area of the hemisphere. The lateral surface area of the rectangular base is 2(20cm x 15cm) = 600 sq cm. The surface area of the hemisphere is 2πr^2, where r is half the diameter of the base, so r = 10cm. Thus, the surface area of the hemisphere is 2π(10cm)^2 = 200π sq cm ≈ 628.32 sq cm. Add the lateral surface area of the base and the surface area of the hemisphere: 600 sq cm + 628.32 sq cm ≈ 1228.32 sq cm. Therefore, the total surface area of the box is approximately 1228.32 sq cm, which is closest to 1325 sq cm (Choice C). Choices A, B, and D are incorrect as they do not represent the accurate calculation of the total surface area of the box.

2. Convert 5 3/4 to a decimal. Round to the nearest tenth.

A. 5.6
B. 5.7
C. 5.8
D. 6

Correct answer: C

Rationale: To convert 5 3/4 to a decimal, we add the whole number part to the fractional part: 5 + 3/4 = 5.75. Rounding 5.75 to the nearest tenth gives us 5.8. Therefore, the correct answer is C. Choice A (5.6) is incorrect because it does not accurately represent 5 3/4. Choice B (5.7) is incorrect as well because it does not reflect the correct conversion. Choice D (6) is incorrect as it does not account for the fractional part of 5 3/4.

3. What is 25% of 200?

A. 50
B. 60
C. 25
D. 30

Correct answer: A

Rationale: To find 25% of a number, you multiply the number by 0.25. So, to calculate 25% of 200, you do 0.25 × 200 = 50. Therefore, the correct answer is A. Choice B (60) is incorrect as it is the result of calculating 30% of 200. Choice C (25) is incorrect as it represents 12.5% of 200. Choice D (30) is incorrect as it is the result of calculating 15% of 200.

4. Multiply: 15 × 52 =

A. 0.0078
B. 0.078
C. 0.78
D. 7.8

Correct answer: D

Rationale: To find the product of 15 and 52, you simply multiply them together: 15 x 52 = 780. Therefore, the correct answer is 7.8. Choices A, B, and C are incorrect as they represent fractions or decimals much smaller than the correct product of 780.

5. How many digits are in the Hindu-Arabic numeral system?

A. Two
B. Ten
C. Twelve
D. Twenty

Correct answer: B

Rationale: The Hindu-Arabic numeral system consists of ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. These ten digits are used as the fundamental symbols to represent numbers in this numerical system. Choice A, 'Two,' is incorrect as there are more than two digits in the system. Choice C, 'Twelve,' is incorrect as it exceeds the total number of digits in the system. Choice D, 'Twenty,' is incorrect as it overestimates the number of digits present in the Hindu-Arabic numeral system.