9. the formula s = √18d can be used to find the speed s of a car in miles per hour when the car needs d feet…

9. the formula s = √18d can be used to find the speed s of a car in miles per hour when the car needs d feet to come to a complete stop after stepping on the brakes. if it took a car 25 feet to come to a complete stop after stepping on the brakes, estimate the speed of the car. truncate the value of √18d, when d = 25, to the tenths place. (example 4)

9. the formula s = √18d can be used to find the speed s of a car in miles per hour when the car needs d feet to come to a complete stop after stepping on the brakes. if it took a car 25 feet to come to a complete stop after stepping on the brakes, estimate the speed of the car. truncate the value of √18d, when d = 25, to the tenths place. (example 4)

Answer

Explanation:

Step1: Substitute d value

Substitute $d = 25$ into the formula $s=\sqrt{18d}$. So we get $s=\sqrt{18\times25}$.

Step2: Calculate product inside square - root

First, calculate $18\times25 = 450$. Then $s=\sqrt{450}$.

Step3: Find square - root and truncate

$\sqrt{450}\approx21.2132$. Truncating to the tenths place, we get $s\approx21.2$.

Answer:

$21.2$