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A helicopter dropped a rescue package from a height of 1,296 feet. Use the formula $t=\frac{\sqrt{h}}{4}$ to find how many seconds it took for the package to reach the ground.
$9\phantom{\rule{0.2em}{0ex}}\text{seconds}$
A window washer dropped a squeegee from a platform 196 feet above the sidewalk Use the formula $t=\frac{\sqrt{h}}{4}$ to find how many seconds it took for the squeegee to reach the sidewalk.
$3.5\phantom{\rule{0.2em}{0ex}}\text{seconds}$
Police officers investigating car accidents measure the length of the skid marks on the pavement. Then they use square roots to determine the speed, in miles per hour, a car was going before applying the brakes.
If the length of the skid marks is d feet, then the speed, s , of the car before the brakes were applied can be found by using the formula,
After a car accident, the skid marks for one car measured 190 feet. Use the formula $s=\sqrt{24d}$ to find the speed of the car before the brakes were applied. Round your answer to the nearest tenth.
Step 1. Read the problem.  
Step 2. Identify what we are looking for.  The speed of a car. 
Step 3. Name what we are looking for.  Let s = the speed. 
Step 4. Translate into an equation by writing the appropriate formula.  
Substitute the given information.  
Step 5. Solve the equation .  
Round to 1 decimal place.  
Step 6.
Check the answer in the problem.
$\phantom{\rule{1em}{0ex}}67.5\stackrel{?}{\approx}\sqrt{24\left(190\right)}$ $\phantom{\rule{1em}{0ex}}67.5\stackrel{?}{\approx}\phantom{\rule{0.2em}{0ex}}\sqrt{4560}$ $\phantom{\rule{1em}{0ex}}67.5\stackrel{?}{\approx}\phantom{\rule{0.2em}{0ex}}\mathrm{67.5277...}$ 

Is 67.5 mph a reasonable speed?  Yes. 
Step 7. Answer the question with a complete sentence.  The speed of the car was approximately 67.5 miles per hour. 
An accident investigator measured the skid marks of the car. The length of the skid marks was 76 feet. Use the formula $s=\sqrt{24d}$ to find the speed of the car before the brakes were applied. Round your answer to the nearest tenth.
$42.7\phantom{\rule{0.2em}{0ex}}\text{feet}$
The skid marks of a vehicle involved in an accident were 122 feet long. Use the formula $s=\sqrt{24d}$ to find the speed of the vehicle before the brakes were applied. Round your answer to the nearest tenth.
$54.1\phantom{\rule{0.2em}{0ex}}\text{feet}$
Solve Radical Equations
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