Unit 6
4 marks · Easy(a) The area A of a square is proportional to the square of its side length s. (b) The first three square numbers are listed in the set S = {1, 4, 9}.
Answer the following:
If s = 5 cm, find the area A. Give your answer in cm².
Describe set S in words using set-builder notation.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) A = 25 cm²
(b) S = {x | x is a square number less than or equal to 9}
Common mistakes: incorrect area formula; incorrect set notation
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Uses formula A = s².
A1 (a) · 1 mark · Finds correct area for s = 5 (25 cm²).
M1 (b) · 1 mark · Describes set using correct mathematical language.
A1 (b) · 1 mark · Correct set-builder notation for S.
Worked solution
(a) Area = s² = 5² = 25 cm².
(b) S = {x | x is a square number and x ≤ 9}.