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1. A waste paper basket has a top ABCD that is a square of side 30cm and a base that is a square of side 20. The line joining the centres of the top and base PQRS is perpendicular to both and is 40cm long.
I've found the diagonals AC and PR of each base.
I don't know how to find the length AP
Heres a picture of the diagram.
Attachment 618126
2. (Original post by Mermaidqueen)
A waste paper basket has a top ABCD that is a square of side 30cm and a base that is a square of side 20. The line joining the centres of the top and base PQRS is perpendicular to both and is 40cm long.
I've found the diagonals AC and PR of each base.
I don't know how to find the length AP
Heres a picture of the diagram.
Attachment 618126
3D triangle, the line joining the centres of the two faces will touch the bottom face at X where PX = 1/2 * PR and similar for the top face.

Then use pythagoras liberally.
3. (Original post by Zacken)
3D triangle, the line joining the centres of the two faces will touch the bottom face at X where PX = 1/2 * PR and similar for the top face.

Then use pythagoras liberally.
I understand why we use 1/2 of PR but i don't get what you do next because if you draw the diagonal line from P to 1/2*AC that triangle isn't going to help get AP
4. (Original post by Mermaidqueen)
I understand why we use 1/2 of PR but i don't get what you do next because if you draw the diagonal line from P to 1/2*AC that triangle isn't going to help get AP
Why would it not?

You can use pythag on triangle PXY to find the length of PY. Then use pytah on triangle APY since you now know the length PY to find AP.

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