A student investigates how light refracts as it passes from air into a perspex block.
They record the angle of incidence, θ1\theta_1θ1, and the angle of refraction, θ2\theta_2θ2, for several different angles.
| Angle of incidence, θ1\theta_1θ1 (∘^{\circ}∘) | Angle of refraction, θ2\theta_2θ2 (∘^{\circ}∘) |
|---|---|
| 0 | 0 |
| 15 | 10 |
| 30 | 19.5 |
| 45 | 28 |
| 60 | 35 |
| 75 | 40.5 |
Using the data, they plot the points on the grid in Figure 5.

On the graph in Figure 5, draw the curve of best fit.