
Education Journalist | Study Abroad Lead
Linear Interpolation Formula is a technique for estimating a function's value between any two known values. It comes in handy for estimating any required value at a known coordinate position. It's a curve fitting method that involves plotting new data points within the range of a discrete set of known data points using linear polynomials.Therefore, the easiest method for predicting a channel from the vector of the supplied channel's estimates is linear interpolation. It can be used to predict data, forecast data, do market research, and a variety of other mathematical and scientific tasks.
| Table of Content |
Key Terms: Linear interpolation, Data points, Interpolation, Data values, Vector, Polynomials, Straight line, Function
Introduction to Linear Interpolation
[Click Here for Sample Questions]
The function of untabulated points can be estimated via interpolation. Interpolation is a technique that can be used to estimate any desired value at a specified coordinate location.
When looking for a value between two data points, linear interpolation comes in handy. As a result, mathematicians refer to it as "filling in the gaps" for tabular data values. The strategy for linear interpolation is to connect the available data points on both the positive and negative sides of the unknown location with a straight line.

Introduction to Linear Interpolation
Also Read: Absolute value formula
Linear Interpolation Formula
[Click Here for Sample Questions]
This formula finds the best fit curve as a straight line using the coordinates of two given values. Then every required value of y at a known value of x will be obtained.
In this formula :
- The first coordinates are x1 and y1.
- The second coordinates are x2 and y2.
- The interpolation point is x, and the interpolated value is y.
Also Read: Slope of secant line formula
Things to Remember
- The technique of determining a value between two points on a line or curve is known as interpolation.
- Interpolation is a technique for simplifying complicated functions by sampling any given data point and interpolating it with a simpler function.
- Commonly Polynomial Interpolation is a method of interpolation that uses polynomials since they are considerably easier to evaluate, differentiate, and integrate.
- When calculating the values between two points, the linear interpolation formula comes in handy. As a result, linear interpolation is also regarded as a means of filling in the gaps in a table format for any value.
- The function of un-tabulated points can be estimated via interpolation.
Also Read:
Sample Questions
Ques. Given a set of numbers (2, 4), (6, 7) and x = 4, what is the value of y at x = 4? (2 Marks)
Ans. x = 4; x1 = 2; x2 = 6; y1 = 4; y2 = 7 are the known values.
The formula for interpolation is as follows:
y=y1+(x-x1)(y2-y1)x2-x1
I.e. y=4+(4-2)(7-4)(6-2)
y=112
Ques. Calculate the estimated height of the boy in the fourth position. (3 Marks)

Ans. x=4; x1=3; x2=5; y1=5; y2=6 (given)
Using linear interpolation formula,
y=y1+(x-x1)(y2-y1)(x2-x1)
Putting the values,
y=5+(4-3)(6-5)(5-3)
y=5+1(1/2)
y=5+0.5
y=5.5
Ques. If x=8 and some set of values are given as (5,3.5), (10,6). Find the value of y. (3 Marks)
Ans. Given, x=8; x1=5; y1=3.5; y2=6
Using linear interpolation formula,
y=y1+(x-x1)(y2-y1)(x2-x1)
Putting the values,
y=3.5+(8-5)(6-3.5)(10-5)
y=3.5+3(2.5/5)
y=3.5+3(1/2)
y=5
Ques. What is the difference between interpolation and extrapolation, and what does interpolation mean? (3 Marks)
Ans. Interpolation is essentially guessing data points that are inside the range of the data you've previously been given and are in the middle of your existing data points. Extrapolation is the process of making educated guesses about data points that are outside the range of your data collection.
Interpolation is the process of estimating a value between two known values in a series of values. Interpolation is a strategy that allows us to estimate the values within a gap in graphical data when the data is accessible on each side of the gap or at a few specific places within the gap.
Ques. What are the different Interpolation types? (3 Marks)
Ans. In mathematical models, there are various forms of interpolations. Here are a few examples:
(i) Linear Interpolation (using linear polynomials to build more data points).
(ii) Polynomial Interpolation (which entails taking a given set of data from the lowest degree polynomial and allowing it to pass through the points in the data set for Interpolation data).
(iii) Bilinear Interpolation (Interpolation type using two distinct variables leading to the formation of a 2D rectilinear grid; Interpolation is done in two different directions, one after the other).
(iv) Spline Interpolation (when an interpolant is a special place-wise polynomial).
Ques. What is the significance of interpolation in statistics? (2 Marks)
Ans. Interpolation is commonly employed in statistical models for commercial and mathematical research since it aids in the prediction of future likely points in data analysis. One can determine where the general consistent trend will lead the pricing (of a product or service), prospective yield (and company growth) or acquire insights into the stock market under a specific market dynamic using the collected sets. In the bond market and the financial sector, financial experts have regularly used this strategy to derive logical conclusions.
Ques. Give an example of Interpolation. (3 Marks)
Ans. When extending a straight line on the graph to predict the growth in the market price of fuel such as petrol or diesel with respect to global market trends such as currency value of a country or increment or decrement in share market values, one gets a data set of points that points towards an increase in fuel price as share market value falls or a currency value declines.
In the physical world, the mass and volume of a given substance may be estimated using a similar plotting method called Interpolation to determine how the volume of a substance varies when the mass of the material increases or decreases.
Ques. The height (in feet) of a tree was measured every five years after it was planted and recorded in the following table:

Use interpolation to estimate the height of the tree eight years after it was planted. (4 Marks)
Ans. We'll choose the two data points closest to this number for our interpolation calculation because we're looking for the tree's height after eight years. So, in the interpolation calculation, we'll use (5, 3.5) and (10, 6) and then replace x = 8 into the formula. We have the following:
y-y=y2-y1x2-x1(x-x1)
y-3.5=6-3.510-5(x-5)
y-3.5=0.5(x-5)
y-3.5=0.5x-2.5
y=0.5x+1
y=0.5(8)+1
y=4+1
y=5
Therefore, the tree was about five feet tall after 8 years.
Ques. Since 1980, the population of a city has been recorded every ten years. To estimate the population in 2009, use the table below and interpolation. (4 Marks)

Ans. Since we want the population in the year 2009, using the year closest to 2009 i.e. (2000,142000) and (2010,153000) and then substitute x=2009 in the formula.
y-y1=y2-y1x2-x1(x-x1)
y-142,000=153,000-142,0002010-2000(x-2000)
y-142,000=11,00010(x-2000)
y-142,000=1,100(x-2000)
y-142,000=1,100x-2,200,000
y=1,100x-2,058,000
y=1,100(2009)-2,058,000
y=151,900
For Latest Updates on Upcoming Board Exams, Click Here: https://t.me/class_10_12_board_updates
Check-Out:







Comments