Square Roots & Cube Roots · Exercise 4 of 6
65 mixed-level square root and cube root questions in the style of IBPS/SBI ("√? = …"), SSC CGL/CHSL, RRB NTPC and Group D, UPSC CSAT, state exams and campus placements. Use them as a timed speed drill.
What will come in place of ? : √? × 4 = 64
√? = 64 ÷ 4 = 16
? = 16² = 256
Answer: 256
What will come in place of ? : √1225 + √? = 50
√1225 = 35
35 + √? = 50 → √? = 15
? = 225
Answer: 225
What will come in place of ? : ∛? = 13
Cube both sides.
? = 13³ = 13 × 13 × 13
= 2,197
Answer: 2,197
What will come in place of ? : √(0.0169 × ?) = 1.3
Square both sides: 0.0169 × ? = 1.69
? = 1.69 ÷ 0.0169 = 100
Answer: 100
What will come in place of ? : √784 ÷ √? = 4
√784 = 28
28 ÷ √? = 4 → √? = 7
? = 49
Answer: 49
√(3 × 27) + √(2 × 32) = ?
3 × 27 = 81 → √81 = 9
2 × 32 = 64 → √64 = 8
9 + 8 = 17
Answer: 17
(√8 × √2)² = ?
√8 × √2 = √16 = 4
4² = 16
Shortcut: (√a × √b)² = a × b = 8 × 2 = 16
Answer: 16
What will come in place of ? : √256 × ∛216 ÷ ? = 24
√256 = 16
∛216 = 6
16 × 6 = 96
96 ÷ ? = 24 → ? = 4
Answer: 4
Find the value of 12² + √144.
12² = 144
√144 = 12
144 + 12 = 156
Answer: 156
If √a = 25 and √b = 7, find √(a − b).
a = 25² = 625
b = 7² = 49
a − b = 576
√576 = 24
Trap: it is not 25 − 7 = 18.
Answer: 24
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