don steward
mathematics teaching 10 ~ 16

Sunday, 22 April 2012

similar triples

if the width of the rectangle is 3cm and the length is 4cm

what are the lengths a , b , and c?

[to avoid fractions, make the width 15cm and the length 20cm]

you can work out the lengths without using pythagoras
because the triangles are similar. a = 4k, b = 3k, c = 9/4k
then use areas of triangles

three similar right angled triangles make up a rectangle

what are the lengths of their sides?

again, you do need to use pythagoras

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