
Answer:
 A)  T = 13/62N +(50 45/62)
 B)  T ≈ 83.9 °F
Step-by-step explanation:
The equation can be written in slope-intercept form by finding the slope (m) and the y-intercept (b). The formulas are ...
 m = (y2 -y1)/(x2 -x1)
 b = y1 -m(x1)
For the given points (111, 74) and (173, 87), the slope is ...
 m = (87 -74)/(173 -111) = 13/62
The y-intercept is ...
 b = 74 -(13/62)(111) = 50 45/62
Then the equation in slope-intercept form is ...
 y = mx +b
 T = 13/62N +(50 45/62)
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For a chirp rate of N=158, the temperature is approximately ...
 T = (13/62)(158) +(50 45/62) = 33 8/62 +50 45/62 = 83 53/62
 T ≈ 83.9 °F