pcp

[barber]

what is the length of the hypoteneuse of a right -angled triangle ,the lengths of the other two sides being 30cm and 72cm

[JoolsTwo]

78cm

[lady_p_gold]

Hooray .. I did it ! Took ages though !

[crofter]

barber There are a few well-known right-angled triangles with integer sides like (3,4,5) and (5,12,13). So if the sides are 3 and 4 units, then the hypotenuse has length 5 units etc.

If the sides of (3,4,5) are scaled up by a factor of 3 (say) then the sides of 9 and 12 give a hypotenuse of length 15 units.

The triangle in question is the (5,12,13)-triangle scaled up by a factor of 6 to give (30,72,78). Hence if the sides are 30 cm and 73cm, thsen the hypotenuse has length 78cm (as given by JimJools and verified by lady_p_gold).

[barmy]

the length of the hypoteneuse is the sqaure root of the sum of the other two sides squared

30x30 + 72x72 = 6084

sq root of 6084 = 78

[Dustybun]

wow! all these Pythagori!!