Interpolation, extrapolation, and curve fitting are techniques used to estimate values of a function at points where data is not explicitly given. Interpolation involves estimating values within the range of known data points, while extrapolation estimates values outside this range. Curve fitting, on the other hand, aims to find a mathematical function that best approximates the given data points, which can be used for both interpolation and extrapolation. These techniques are widely used in various fields, including engineering, science, and statistics, to analyze data, make predictions, and gain insights into underlying trends.