Copyright © University of Cambridge. All rights reserved.
Cong who goes to St. Peter's RC Primary, Aberdeen, sent in a correct solution to this problem. The key to answering it is to be sure you know what you mean by "different" triangles. Cong found 7 different triangles could be drawn on the nine-pin board which he drew:
He also sent in a table which gave some more information about each triangle:
Well answered, Cong, thank you.