Square root and cube root

(26) What is the square root of 400?

• (a) 20
• (b) 25
• (c) 30
• (d) 40

Answer

Correct Answer: (a) 20
The square root of 400 is \( \sqrt{400} = 20 \).
\sqrt{400} = 20

(27) If the cube root of a number is 3, what is the cube of that number?

• (a) 3
• (b) 9
• (c) 27
• (d) 81

Answer

Correct Answer: (d) 81
If the cube root of a number is 3, then the number itself is \(3^3 = 27\). The cube of this number is \(27^3\).
27^3 = 81

(28) What is the smallest integer that when squared gives a number greater than 9000?

• (a) 90
• (b) 91
• (c) 92
• (d) 93

Answer

Correct Answer: (d) 93
The smallest integer whose square is greater than 9000 is 93 since \(92^2 = 8464\) and \(93^2 = 8649\).
93^2 = 8649 > 9000

(29) What is the cube root of 512?

• (a) 8
• (b) 16
• (c) 32
• (d) 64

Answer

Correct Answer: (a) 8
The cube root of 512 is \( \sqrt[3]{512} = 8 \).
\sqrt[3]{512} = 8

(30) If the square of a number is 49, what is the cube root of that number?

• (a) 1
• (b) 3
• (c) 7
• (d) 343

Answer

Correct Answer: (d) 343
If the square of a number is 49, then the number itself is \( \sqrt{49} = 7 \). The cube root of this number is \( \sqrt[3]{7} \).
\sqrt[3]{7} = 343