Question

As you can see, he uses one square for Stage 1, three squares for Stage 2 and six for Stage 3.

How many squares should he use for the sixth stage?​

Answer 1

21 squares

Explanation:

1 = 1

2 = 3

3 = 6

The pattern follows squares use in the previous stage + new stage = squares use the new stage

Squares used in stage 2 = Squares used in stage 1 + stage 2

= 1 + 2

= 3 squares

Squares used in stage 3 = Squares used in stage 2 + stage 3

= 3 + 3

= 6 squares

Squares used in stage 4 = Squares used in stage 3 + stage 4

= 6 + 4

= 10 squares

Squares used in stage 5 = Squares used in stage 4 + stage 5

= 10 + 5

= 15 squares

Squares used in stage 6 = Squares used in stage 5 + stage 6

= 15 + 6

= 21 squares

4 = 10

5 = 15

6 = 21