Quandaries and Queries Name: Raj Who is asking: Student Level: Secondary Question: Draw a rectangle with sides of 3 and 4. Divide the sides into 3 and 4 equal parts respectively. Draw squares joining the points on the sides of the rectangle. You will have 12 small squares inside the 3 x 4 rectangle. If you draw a diagonal of the rectangle, it will intersect 6 of the the 12 smaller squares. Similarly, if you have a 4 x 10 rectangle, the diagonal would intersect 12 of the 40 squares inside the rectangle. Is there an algebric equation that determines the number of squares that will be intersected by the diagonal of a rectangle? Thank you, Hi Raj, (Number of squares intersected) = 1 + (number of horizontal lines crossed) + (number of vertical lines crossed) - (number of vertices passed through) Thus for a 3 by 4, there are 2 horizontal, 3 vertical, and no vertices: Number = 1+3+2 = 6. For the 4 by 10 there are 3 horizontal, 9 vertical, and one vertex: Number = 1 + 3 + 9 - 1 = 12. Chris Go to Math Central