Answer:
x = 1.5 ft.
Step-by-step explanation:
This is a right triangle, of course, so the Pythagorean Theorem applies.
Looking at this figure, I can see that the hypotenuse is 3.9 feet and one of the legs is 3.6 and feet.
The only side length missing is the second leg.
Here, I am solving for the second leg.
[tex]a^2+b^2=c^2[/tex]
[tex]3.6^2+x^2=3.9^2[/tex]
[tex]12.96 + x^2=15.21[/tex]
[tex]15.21-12.96=2.25[/tex]
[tex]x^2=2.25[/tex]
[tex]x=1.5[/tex]
Therefore, the length of the missing side is 1.5 ft.
