PPL Oral Exam: How to calculate Take off ground roll ?

This is the most common topic for those who are having PPL Oral and Practical Exam. As American Pilot Academy, We r trying to solve a numerical problem related to determining take-off roll using a take-off distance graph and Landing roll using landing sheet of Aircraft.
Lets Start giving The parameters are which Temp: 15 C, Press. alt: 5850 ft, TO Gross Weight: 2500 lbs, headwind components : 20 Knots.
We have got the following graph (Pls check and follow solid red lines):

Solid/ Red dashed line shows us how to solve the problem with the parameters given.
It s very easy to reach the Normal Take off distance and Short Field Take Off Distance by using the reference lines in both vertically and horizontally.

You start with the outside air temperature. Pick what the instrument in your cockpit indicates, and go from the temperature axis straight up until you intercept the line which is closest to your given pressure altitude. This can be read directly from the altimeter if it is set correctly. You can try to interpolate between lines, but to be safe pick the next higher value.
Next, move horizontally to the first reference line. From there, follow the slope of the lines until you intercept the x-position which corresponds to your aircraft’s mass. If you start between two lines, you should move such that the relative vertical distance to the neighboring lines does not change. Note that the take-off mass is also a value you should know already if your preflight was done properly.

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