Part (e)
See the diagram below that mentions this part.
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Part (f)
See the diagram that mentions this part. It's in a separate image.
The item can be anything really. I'm going to add a trampoline which is a square shown in purple. The square is rotated 45 degrees so it looks like a diamond shape. The rotation isn't necessary but I figured to spice things up compared to the other figures which were mostly squares or rectangles. If we split the purple square into 4 triangles, and apply the pythagorean theorem, then we can find the length of each side of the purple square to be roughly 2.828 cm.
Scaling things up, the trampoline in real life is 2*2.828 = 5.656 meters along each dimension.
With any square the angles are always 90 degrees.