Sum. To build the triangle, start with 1 at the top, then continue placing numbers below it in a triangular pattern. Each number is the numbers directly above it added together.
85 = 10x+15
70 = 10x
x = 7
180-85 = 95 = z
Answer:

Step-by-step explanation:
Given that x and y are proportional and the equation relating them is
y = rx ← r is the constant of proportionality
To find r use any ordered pair from the table
Using x = 9, y = 4.5 , then
4.5 = 9r ( divide both sides by 9 )
= r , that is
r = 