The length of the hypotenuse is 30 ft and this can be determined by using the Pythagorean theorem.
Given :
The legs of an isosceles right triangle have a length of [tex]15\sqrt{2}[/tex] ft.
The following steps can be used in order to determine the length of the hypotenuse:
Step 1 - The Pythagorean theorem can be used in order to determine the length of the hypotenuse.
Step 2 - According to the given data, the legs of an isosceles right triangle have a length of [tex]15\sqrt{2}[/tex] ft.
Step 3 - So, the length of the hypotenuse is calculated as:
[tex]H^2 = 2\times (15\sqrt{2} )^2[/tex]
Step 4 - Simplify the above expression.
[tex]H =30\;{\rm ft}[/tex]
Therefore, the correct option is D).
For more information, refer to the link given below:
brainly.com/question/21149612