Two sides of an isosceles triangle have lengths of 3 and 10. find the length of the third side.

The third side must be 10:  {3, 10, 10}; {10, 3, 3} is not possible.

Step-by-step explanation:

Everything depends on our understanding of "isosceles."

This term indicates that two sides of a given triangle are equal.

If two sides of an isosceles triangle have lengths of 3 and 10, then:

Either 1)  Two sides have length 10 and the third side has length 3.  This is certainly possible

or

2)  sides have length 3 and the third side has length 10.  This is NOT possible, since 3 + 3 adds up to 6, which is less than 10.

the answer is a if my teacher taught me correct