New SAT Math Workbook

Going through the digits from 0 to 9 this could be 3

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Unformatted text preview: digit of the square root. Example: Find the number of digits in the square root of 328,329. Solution: Pair the numbers beginning at the decimal point. 32 83 29 . Each pair will give one digit in the square root. Therefore the square root of 328,329 has three digits. If we were asked to find the square root of 328,329, we would look among the multiple-choice answers for a three-digit number. If there were more than one, we would have to use additional criteria for selection. Since our number ends in 9, its square root must end in a digit that, when multiplied by itself, ends in 9. Going through the digits from 0 to 9, this could be 3 (3 · 3 = 9) or 7 (7 · 7 = 49). Only one of these would appear among the choices, as this examination will not call for extensive computation, but rather for sound mathematical reasoning. Example: The square root of 4624 is exactly (A) 64 (B) 65 (C) 66 (D) 67 (E) 68 Solution: Since all choices contain two digits, we must reason using the last digit. It must be a number that, when multiplied by itself, will end in 4. Among the choices, the only possibility is 68 as 642 will end in 6, 652 will end in 5, 662 in 6, and 672 in 9. www.petersons.com 150 Chapter 10 Exercise 4 Work out each problem. Circle the letter that appears before your answer. 1. The square root of 17,689 is exactly (A) (B) (C) (D) (E) 2. 131 132 133 134 136 5. 4. The square root of 25.6036 is exactly (A) (B) (C) (D) (E) 5.6 5.06 5.006 5.0006 5.00006 The number of digits in the square root of 64,048,009 is (A) (B) (C) (D) (E) 4 5 6 7 8 Which of the following square roots can be found exactly? (A) (B) (C) (D) (E) .4 .9 .09 .02 .025 3. The square root of 222.01 is exactly (A) (B) (C) (D) (E) 14.3 14.4 14.6 14.8 14.9 www.petersons.com Roots and Radicals 151 RETEST Work out each problem. Circle the letter that appears before your answer. 1. The sum of 2 8 , 4 50 , and 3 18 is (A) (B) (C) (D) (E) 2. 33 6 9 76 33 2 135 6 136 2 1 2 180 and 20 is 2 5 6. Find (A) (B) (C) (D) (E) The difference between (A) (B) (C) (D) (E) 1 160 10 2 16 5 5 2 16 5 11 5 5 2 5 5 a2 a2 + b2 b2 a2 b2 a b 2a b a2 b a2 b2 7. The square root of 213.16 is exa...
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This note was uploaded on 08/15/2010 for the course MATH a4d4 taught by Professor Colon during the Spring '10 term at Embry-Riddle FL/AZ.

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