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Linear Interpolation. (a quick how-to). Wendi Morrison 2010. Situation. Distance vs. Time. Start with data, not necessarily linear. What was the distance at 35 s?. Use a straight line to estimate a value between known data. When was the distance 200 m?. What was the distance at 35 s?.
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Linear Interpolation (a quick how-to) Wendi Morrison 2010
Situation Distance vs. Time • Start with data, not necessarily linear. What was the distance at 35 s? • Use a straight line to estimate a value between known data. When was the distance 200 m?
What was the distance at 35 s? • Choose the two points that capture 35 s. • Plot the points to make a triangle. • Label what you know. 160 • Make a smaller triangle. • Label the triangle sides. 90 + x 70 x x The triangle is this shape because the graph goes up… 90 30 5 35 40 • Solve the ratio: 10 Round to the same precision as 35 s. • Add x to the lower value: • 90 + 35 = 125 The distance at 35 s was about 125 m.
When was the distance 200 m? • Choose the two points that capture 200 m. • Label what you know. • Plot the points to make a triangle. 250 • Make a smaller triangle. • Label the triangle sides. 200 90 40 160 • Solve the ratio: 40 x 40 + x 50 10 Round to the same precision. • Add x to the lower value: • 40 + 4 = 44 The distance was 200 m at about 44 s.