Help me pls its Pythagorean theorem I need help

Answer:
the answer is 3.81
but rounding it it will be 3.8 meters
Step-by-step explanation:
Pythagorean theorem says
a²+b²=c²
so,
take take the Lowest measurement as a² which will be 7 and take 8 as the hypotenuse or the longest side which is c²
then put it all together you get
7²+x²=8²
we made b as x because we will be finding b
then substitute the values
x²=8²-7²
x²=64-49
x²=15
to remove that square from the x you then put square root in both
✓x²=✓15
press in the calculator, root of 15 will be about 3.81
now we got
x=3.81
x is the missing measurement