Answer:
3
Step-by-step explanation:
#Equation of m?
m = E/c²
E = mc²
E : c² = m
E/c² = m
So, the formula of m is E/c²
by using Pythagoras law
h²=p²+b²
13²=9²+b²
169-81=b²
b=√88=2√22m is your answer