we know that
Applying the Pythagoreamn Theorem
c^2=a^2+b^2
where
c is the hypotenuse
a and b are the legs
In this problem
a=7 units (horizontal leg)
b=5 units (vertical leg)
substitute
c^2=7^2+5^2
c^2=49+25
c^2=74
c=8.6 units
therefore
the answer is
the hypotenuse is about 8.6 units long
