Using the Pythagorean theorem, the formula is:
[tex]a^2+b^2=c^2[/tex]
Where:
a = 7.1 km
c = 8.4 km
And we will find the side b.
Substitute the values:
[tex]7.1^2+b^2=8.4^2[/tex]
And solve for b:
[tex]\begin{gathered} 50.41+b^2=70.56 \\ \text{subtract 50.41 on both sides} \\ 50.41+b^2-50.41=70.56-50.41 \\ b^2=20.15 \\ b=\sqrt[]{20.15}=4.5 \end{gathered}[/tex]
Answer: b = 4.5 km
