5.5 Finding an algebraic expression for the nth terms: Square patterns

N5. Algebraic expressions and formulae

Question

The diagram shows patterns of white and grey squares.

DiagramNumber of grey squares (G)Number of white squares (W)Total number of squares (Q)
1101
2189
317825
4173249
5
649pq

(a) Find the values of p and q. [2]

(b) (i) Write down an expression, in terms of n, for the total number of squares (Q) for Diagram n. [1]

(ii) Explain why it is not possible to have a diagram with a total of 226 squares. [1]

(c) Write an equation connecting G, W and Q. [1]

(d) If there are 161 grey squares in Diagram 10, calculate the number of white squares. [2]

Solution