Answer:
a=3
Step-by-step explanation:
hypotenuse theorem: c^2=a^2+b^2
plug it in, where c=5 and b=4.
5^2=a^2+4^2
25=a^2+16
subtract 16 from both sides:
9=a^2
the square root of 9 is 3, so a=3.
