You know that two expressions are equivalent when if you substitute in your values and simply the expressions, they have the same answer.
We can use the Pythagorean theorem to solve for the perimeter of the kite.
a² + b² = c²
3² + 4² = UV²
9 + 16 = UV²
25 = UV²
√25 = √UV²
5 = UV
In the kite, adjacent sides are the same so UV = VW
3² + 9² = UX²
9 + 81 = UX²
90 = UX²
√90 = √UX²
9.49 ≈ UX or 3√10 ≈ UX
Now, add to find the perimeter.
5 + 5 + 9.49 + 9.49 or 5 + 5 + 3√10 + 3√10
28.98 or 10 + 6√10
Therefore, the perimeter is approximately 28.98 or 10 + 6√10
Best of Luck!