Matchstick pattern challenge
A row of squares is made from matchsticks.
1 square uses 4 matchsticks
2 squares in a row use 7 matchsticks
3 squares in a row use 10 matchsticks
How many matchsticks will 20 squares in a row use?
Word Problem
A bridge is built across a river. One quarter of the bridge is over the left bank of the river and one third of the bridge is over the right bank. The river is 120 m wide. How long is the bridge?
Each new square adds 3 more matchsticks because one side is shared.
ReplyDeleteSo the pattern is:
4, 7, 10, 13, ...
This is a sequence increasing by 3 each time.
For 20 squares:
Matchsticks = 4 + 19 × 3
Matchsticks = 4 + 57
Matchsticks = 61