Linear Interpolation: Given a pair of (x1,y1), (x2,y2) and x3 predict (x3,y3)

[Han]

In general your interpolation (and its accuracy) depends on the relationship between the parameters. For your example, if you use \( PV=nRT \) and pressure \( P \) is kept constant, then in this case a linear interpolation would be fine since
\[ V = \underbrace{\frac{nR}{P}}_{\text{slope}} \cdot T \]
So since \( n \), \( R \) and \( P \) are constant, then \( V \) is a linear function of \( T \). This should enable you to interpolate the volume provided the pressure is fixed at 100k pascals.

Haven't tested this, but using a linear fit with your known values and then using the trace feature should allow you to figure out the interpolated volume.