The length of the purple wire that Amanda needs to buy to make a triangle is 4 in.
Step-by-step explanation:
Given:
Amanda has 4 in of green wire
8 in of red wire
Length of purple wire, l = ?
We know,
In an isosceles triangle two sides are equal.
If Amanda wants to make a triangle and buy a wire that could perfectly fit to make a third side then the minimum length of the wire should be 4 in as one of the sides of a triangle is 4 in.
Therefore, the length of the purple wire that Amanda needs to buy to make a triangle is 4 in.