Sqrt = Square Root

A student is attempting to calculate the square root of 18. His work is shown below. Which statement below best applies to his mathematical reasoning?

Givin sqrt 18 I observe that 18 is not a perfect square. I notice the perfect squares closest to 18 are 16 and 25, so I estimate the answer to fall somewhere between those numbers. Since 18 is closer to 16, I estimate that sqrt 18 = 17

A.

18 is a perfect square, and the radical could have been evaluated directly.

B.

16 and 25 are not perfect squares, and therefore the student should not have chosen those numbers to estimate sqrt 18

C.

The student did not evaluate sqrt 16 and sqrt 25 before estimating sqrt 18

D.

The student has made no error. sqrt 18 = 17

Question

Mathematics

Marilyn Neal

12 May, 22:45

Sqrt = Square Root

A student is attempting to calculate the square root of 18. His work is shown below. Which statement below best applies to his mathematical reasoning?

Givin sqrt 18 I observe that 18 is not a perfect square. I notice the perfect squares closest to 18 are 16 and 25, so I estimate the answer to fall somewhere between those numbers. Since 18 is closer to 16, I estimate that sqrt 18 = 17

A.

18 is a perfect square, and the radical could have been evaluated directly.

B.

16 and 25 are not perfect squares, and therefore the student should not have chosen those numbers to estimate sqrt 18

C.

The student did not evaluate sqrt 16 and sqrt 25 before estimating sqrt 18

D.

The student has made no error. sqrt 18 = 17

+1

Answers (1)

Know the Answer?

Kael Miller · Answer 1

The answer to this question is C. The student did not evaluate sqrt 16 and sqrt 25 before estimating sqrt 18. The square roots of 16 and 25 are 4 and 5 respectively. He should have esimated that sqrt (18) is close to 4.2 instead of 17.