Similar Triangles (a)

THINGS TO DO

You should have one obtuse and one acute Isotile.

Can you put the two Isotiles together, so that a new shape is formed which is a triangle similar to the obtuse one on the left here?

It will be bigger, of course. The base of the triangle you see on the left becomes a sloping side. The new base will be formed with a join where two Isotiles meet.

Remember that an acute Isotile has base angles of 72° and an apex of 36°. The obtuse Isotile has small angles of 36° and an obtuse angle of 108°. Check that your new similar triangle has the same angles still.

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