The linear equation from the graph is given as:

$y = mx + b$ where:

• $m = 0.29587$ (slope)
• $b = 93.687$ (y-intercept)
• $x$ represents the temperature (in °C)
• $y$ represents the pressure (in kPa)

We need to find the pressure $y$ at a temperature of $x = 21.3$ °C. Substituting $x = 21.3$ into the equation:

$y = 0.29587 \cdot 21.3 + 93.687$

Let me calculate that.

$y = 0.29587 \cdot 21.3 + 93.687 = 6.301 + 93.687 = 99.99$

The pressure at 21.3 °C is 99.99 kPa.

Would you like more details or have any questions? Here are some related questions:

1. How does the correlation coefficient $r = 0.99999$ affect the accuracy of the fit?
2. What does the root mean square error (RMSE) tell us about the linear fit quality?
3. How does temperature generally affect pressure in a system like this?
4. If the slope $m$ were to change, how would it affect pressure predictions?
5. Can this linear model be used for temperature values beyond the data range shown?

Tip: Always check the units when working with real-world equations to ensure correct conversions.