Answer:
Option D 700 inches.
Explanation:
Given is a graph which shows the height of a staircase in inches based on a certain number of stairs.
Let us consider the no of stairs as x and vertical height of stairs as y.
y is directly proportionl to x.
The stair case elevation is a straight line starting with (0,0) and a point (50,350)
Hence we can write y = 7x
When no of stairs = x =100, we get
y = 7(100) = 700 inches.
Option D 700 inches.