3. Match the problem with one of the following equations where $x$ represents the unknown in the problem. Flying at a speed of 212 miles per hour, how long will it take for an airplane to travel 37 miles?
$x-37=212$
$37-x=212$
$212 x=37$
$37 x=212$
$x+37=212$

Step 1 ：Match the problem with one of the following equations where $x$ represents the unknown in the problem. Flying at a speed of 212 miles per hour, how long will it take for an airplane to travel 37 miles?

Step 2 ：The problem is asking for the time it takes for an airplane to travel a certain distance at a certain speed. This is a classic distance = speed * time problem. The equation that represents this problem is distance = speed * time, or in this case, 37 = 212 * x. So, the correct equation is $37 = 212x$.

Step 3 ：Substitute the given values into the equation. The distance is 37 miles and the speed is 212 miles per hour. So, the equation becomes $37 = 212x$.

Step 4 ：Solve the equation for $x$ to find the time. Dividing both sides of the equation by 212 gives $x = \frac{37}{212}$.

Step 5 ：Calculate the value of $x$ to get the time. $x = \frac{37}{212} \approx 0.175$ hours.

Step 6 ：Final Answer: The correct equation that represents the problem is $37 = 212x$ and the time it takes for the airplane to travel 37 miles at a speed of 212 miles per hour is approximately \(\boxed{0.175}\) hours.