Step 7. To mark the stair railing, hold it in place, resting along the stairs, and mark it for the angled cut. Pre-drill the landing and treads for the balusters, using a special stair bit that drills the hole and then creates a thread to accept the baluster bolts.
What is interpolation? Interpolation is the process of estimating unknown values that fall between known values. In this example, a straight line passes through two points of known value. You can estimate the point of unknown value because it appears to be midway between the other two points. The interpolated value of the middle point could be 9.5.
Interpolation can be used on charts as well to determine what your variable would be when your given lies between two sets of data on the chart. An example would be if you had the average temperature of 80 degrees for your favorite beach on May 1 but 100 degrees for June 1.