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This question is about isosceles triangles with an area of 9 cm$^2$.

Each vertex of the triangle must be at a grid point of a square grid,
so all the vertices will have whole number coordinates.

One of the vertices must be at the point (20, 20).

How many different triangles satisfy these four conditions?

Try to find them all. You may wish to use the interactivity below.

Can you explain how you know that you have found them all?

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