Answer:
the third side is 5 2/3 in.
s - 1
Step-by-step explanation:
a = side 1
b = side 2
c = side 3
a + b + c = 15
a = b - 4 => b = a + 4
c = a + 3
a + a + 4 + a + 3 = 15
3a + 7 = 15
3a = 8
a = 8/3 = 2 2/3 in
b = a + 4 = 6 2/3 in
c = a + 3 = 5 2/3 in
This one is very simple.
create a simple equation to find out
15 = 12 + x
subtract 12 from each side
x= 3
the missing number is 3
or, to be even simpler, take the total, subtract the total from the number you know and the difference is the missing number.
hope I helped
ALSO, we can check going down vertically. 3 + 10 =13. this is the total listed at the bottom.