Chapter-1 A Square and A Cube — Online MCQ Test
MATHS · Grade 8 · CBSE(NCERT)
Practice Chapter-1 A Square and A Cube with a free chapter-wise online MCQ test.
This chapter covers: perfect square - square root - radicals - perfect cube - cube root - prime factorisation - long division method - estimating roots.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-1 A Square and A Cube — Important Questions & Answers
What is a perfect square?
- A. A number that is the product of two equal integers
- B. A number divisible by 2
- C. A number greater than 10
- D. A number with all digits the same
Answer: A. A number that is the product of two equal integers
A perfect square is obtained by multiplying an integer by itself, such as 4 = 2×2, 9 = 3×3.
A perfect square is obtained by multiplying an integer by itself, such as 4 = 2×2, 9 = 3×3.
Which of the following is a perfect square?
- A. 35
- B. 49
- C. 50
- D. 48
Answer: B. 49
49 = 7 × 7, making it a perfect square. The others are not products of equal integers.
49 = 7 × 7, making it a perfect square. The others are not products of equal integers.
Find √225.
- A. 13
- B. 14
- C. 15
- D. 16
Answer: C. 15
√225 = 15 because 15 × 15 = 225.
√225 = 15 because 15 × 15 = 225.
If a number's prime factorisation is 2² × 5², what is its square root?
- A. 10
- B. 20
- C. 100
- D. 5
Answer: A. 10
2² × 5² = (2 × 5)² = 10². Therefore, √(2² × 5²) = 2 × 5 = 10.
2² × 5² = (2 × 5)² = 10². Therefore, √(2² × 5²) = 2 × 5 = 10.
If √(x + 5) = 7, then x = ____.
- A. 44
- B. 49
- C. 54
- D. 64
Answer: A. 44
√(x + 5) = 7 means x + 5 = 49, so x = 44. Squaring both sides gives us the value of x.
√(x + 5) = 7 means x + 5 = 49, so x = 44. Squaring both sides gives us the value of x.