Pretty easy middle school math

3

Step-by-step explanation:

If we use pythagoras theorem we know a^2+b^2=c^2

c being the hypoeneuse

so we half the 8 to get the dimensions of the right angle so the bottom side is 4cm and then we use the hypotenuese which is 5 and plug it in so

a^2+4^2=5^2

a^2+16=25

-16 from both sides

a^2=9

square root both sides

a=3

the answer is b i just did that

step-by-step explanation:

1/4 because there is 4 grades.