Question

Anja is creating a triangle using three straws. The two shorter straws have lengths of 20 cm and 21 cm. How long, in centimeters, should the third straw be for Anja to create a right triangle?

Answer 1

A²+B²=C²
20²+21²=C²
400+441=C²
841=C²
√841=C²
29=C

Answer 2

Given

Anja is creating a right triangle using three straws.

The two shorter straws have lengths of 20 cm and 21 cm.

Find the how long, in centimeters, should the third straw.

To proof

this question diagram is given below

Now apply the pythagorus property

Hypotenuse² = Base² + Perpendicular²

AB² = BC² +CA²

take

BC =  20 cm

and

AC =  21 cm

Put this in the above equation

we get

AB² = BC² +CA²

     = 20² + 21²

     = 400 + 441

    = 841

    = √ 841

    =  29cm

The third straw be for Anja to create a right triangle is 29cm.

Hence proved