Solve problems with or without a calculator Level 4

The area of a triangle is 12cm2. What are the possible lengths of base and height? Right-angled triangles have half the area of the rectangle with the same base and height. What about non-right-angled triangles? What other formulae for the area of 2-D shapes do you know? Is there a formula for the area of every 2-D shape? ................
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