Evaluate sqrt(6084) by factorization method?
View answer & explanation Ans: 78
Correct Answer: 78
78 x 78 = 6084, so the square root of 6084 is 78.
FPSC · Other · N/A
Solved square roots and cube roots MCQs — 30 questions on square roots, cube roots, perfect squares and cubes, and least and greatest square and cube problems, with verified answers and explanations. Free online practice for FPSC, PPSC, NTS and all one-paper exams. Covers square roots and cube roots.
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30
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About this paper
This is the Arithmetic: Square Roots and Cube Roots solved MCQ bank from Advanced FPSC & Other Federal Model Papers (Edition 32): 30 published questions (book pp. 780-782, all 30 printed) on evaluating square and cube roots, least and greatest perfect squares and cubes, and numbers to add, subtract, multiply or divide to reach a perfect square or cube. Every answer was re-solved from scratch against the printed Answer Key, and every question carries a worked explanation.
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30 solved MCQs shown directly below
Correct Answer: 78
78 x 78 = 6084, so the square root of 6084 is 78.
Correct Answer: 1213
1213 x 1213 = 1471369, so the square root is 1213.
Correct Answer: 1 1/4
1 9/16 = 25/16, and sqrt(25/16) = 5/4 = 1 1/4.
Correct Answer: 0.03
0.03 x 0.03 = 0.0009, so the square root is 0.03.
Correct Answer: 170/11
sqrt(0.289/0.00121) = sqrt(28900/121) = 170/11, as in solved example (3).
Correct Answer: 900
The LCM of 10, 12, 15 and 18 is 180, and the smallest multiple of 180 that is a perfect square is 180 x 5 = 900 = 30^2.
Correct Answer: 99856
316^2 = 99856 and 317^2 = 100489 (six digits), so 99856 is the greatest five-digit perfect square.
Correct Answer: 69
The next square above 1780 is 43^2 = 1849, and 1849 - 1780 = 69.
Correct Answer: 14
14 x 14 x 14 = 2744, so the cube root is 14.
Correct Answer: 50
4320 = 2^5 x 3^3 x 5, so multiplying by 2 x 5^2 = 50 completes every exponent to a multiple of 3.
Correct Answer: 253
253 x 253 = 64009, so the square root is 253.
Correct Answer: 240
272^2 - 128^2 = (272 - 128)(272 + 128) = 144 x 400 = 57600, whose square root is 240.
Correct Answer: 6
sqrt(15876) = 126, so the units digit of the root is 6.
Correct Answer: 0.4
0.4 x 0.4 = 0.16, so the square root is 0.4.
Correct Answer: 70
sqrt(50) x sqrt(98) = sqrt(4900) = 70.
Correct Answer: 0.09
The keyed answer is 0.09, whose square root is 0.3. Note the printed item also admits 9, whose square root is 3, so as worded it has two correct options; the keyed answer is retained here.
Correct Answer: 213444
The LCM of 21, 36 and 66 is 2772, and the smallest multiple of 2772 that is a perfect square is 2772 x 77 = 213444 = 462^2.
Correct Answer: 3600
The LCM of 3, 4, 5, 6 and 8 is 120, and the smallest multiple of 120 that is a perfect square is 3600 = 60^2.
Correct Answer: 6
294 = 2 x 3 x 7^2, so multiplying by 2 x 3 = 6 gives 42^2.
Correct Answer: 3
5808 = 2^4 x 3 x 11^2, so multiplying by 3 completes the square to 132^2.
Correct Answer: 30
1470 = 2 x 3 x 5 x 7^2, so dividing by 2 x 3 x 5 = 30 leaves 49 = 7^2.
Correct Answer: 81
741^2 = 549081, and 549162 - 549081 = 81.
Correct Answer: 4
The next square above 680621 is 825^2 = 680625, and 680625 - 680621 = 4.
Correct Answer: 9801
99^2 = 9801 and 100^2 = 10000 (five digits), so 9801 is the greatest four-digit perfect square.
Correct Answer: 1024
32^2 = 1024, and 31^2 = 961 has only three digits, so 1024 is the least four-digit perfect square.
Correct Answer: 124
Equal rows and trees per row means rows^2 = 15376, and 124^2 = 15376, so there are 124 rows.
Correct Answer: .06
0.06 x 0.06 x 0.06 = 0.000216, so the cube root is 0.06.
Correct Answer: 9261
21^3 = 9261 and 22^3 = 10648 (five digits), so 9261 is the largest four-digit perfect cube.
Correct Answer: 5
675 = 3^3 x 5^2, so multiplying by 5 completes the cube to 15^3.
Correct Answer: 450
3600 = 2^4 x 3^2 x 5^2, so dividing by 2 x 3^2 x 5^2 = 450 leaves 8 = 2^3.
Source & verification
Built by GK360 from verified bank questions — every answer rechecked before publishing.
Questions
30 questions, all 30 printed in the book. No item was dropped: every keyed answer was verified by re-solving.
Evaluating square roots such as sqrt(6084) and sqrt(1471369), cube roots such as the cube root of 2744, the greatest and least four- and five-digit perfect squares, and the smallest number to add, subtract, multiply or divide to make a perfect square or a perfect cube.
Yes. Every published answer was re-solved from scratch and checked against the book's printed Answer Key on p. 782; all 30 published answers agree with the key. One item carries a reading note rather than an override: Q16's keyed answer is 0.09 (square root 0.3), but option (d) 9 also has a rational square root (3), so the printed item as worded admits two correct options — that is stated in the question's explanation.
Square root and cube root questions of this form appear in FPSC, PPSC, NTS, OTS and other one-paper exams, as well as CSS MPT-style quantitative sections, so the bank is tagged for all of them.
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