Triangle area and transformations
Triangle area is half of base times height, and slides, flips and turns move a shape without changing its size.
A worked example
A triangle with base 14 cm and height 9 cm has area 14 x 9 ÷ 2 = 63 cm².
The mistake people actually make
Halve the answer after multiplying base by height. A translation slides, a reflection flips and a rotation turns, and none of them changes the size.