Question

The perimeter of an isosceles triangle is 1m, and the legnth of the base is equal to 0.4m. Find the legnth of a leg?

Answer 1

An isosceles triangle consists of two legs with equal length, and a base. So, we can call its three sides
`b, l, l`, where
`b` stands for base, and
`l` stands for leg.

Since the perimeter
`2p` is the sum of the three sides, we have

`2p = b+l+l = b+2l`

In this case, the lengths of perimeter and base are known, so let's plug those values in the formula:

`1 = 0.4+2l`

In order to solve for
`l`, let's subtract 0.4 from both sides...

`0.6 = 2l`

...and divide both sides by 2:

`0.3 = l`

So, the legnth of a leg is 0.3

Answer 2

Your answer would be 0.3m.

This is because an isosceles triangle has two sides of the same length, usually on either side above the base, which means we can first do 1 - 0.4 = 0.6m to get the total amount that the two sides add up to, and then 0.6 ÷ 2 = 0.3 to get how long each side is.

I hope this helps!