The Peyto Glacier near Banff receded (melted) 1.5 km between 1933 and 1993. What was the average annual rate of melt in metres? Convert 1.5 into metres then find the yearly average.

The size of the largest square is 36m². To find for the measures of the squares, use the common factors of 42 and 60. Among the common factors, choose the greatest.
Find the factors of 42 using the listing method.
42 - 1, 2, 3, 6, 7, 14, 21, 42
Find the factors of 60 using the listing method also.
60 - 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
Identify the common factors of 42 and 60.
42 - 1, 2, 3, 6, 7, 14, 21, 42
60 - 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
Common Factors: 1, 2, 3, 6
Therefore, the size of the largest square is 36m² since 6m x 6m is equals to 36m².