Answer:
There is a right angled triangle, in which,
Perpendicular = 7 cm
Hypotenuse = 13 cm
Base = b cm
As we know the formula for "Pythagorus theorem":
\begin{gathered}H^2=B^2+P^2\\\\13^2=b^2+7^2\\\\169=b^2+49\\\\169-49=b^2\\\\b^2=120\\\\b=\sqrt{120}\ cm\end{gathered}
H
2
=B
2
+P
2
13
2
=b
2
+7
2
169=b
2
+49
169−49=b
2
b
2
=120
b=
120
cm