Question 227708
Two vehicles, a car and a truck. leave an intersection at the same time. The car heads east at an average speed of 60 miles per hour, while the truck heads south at an average speed of 20 miles per hour.  Find an expression for their distance apart d in miles at the end of t hours.


Step 1.  distance= speed * time.


Step 2.  Let 60t be the car traveling EAST at 60 miles per hour after t hours


Step 3.  Let 20t be the distance of the truck traveling SOUTH at 20 miles per hour after t hours.


Step 4.  Use the Pythagorean Theorem to find the distance d (hypotenuse) given as the sum of the squares of the legs (legs for our example given as 60t and 20t) is equal to the square of the hypotenuse d.


{{{d^2=(60t)^2+(20t)^2}}}


{{{d^2=3600t^2+400t^2}}}


{{{d^2=4000t^2}}}


Take the square root to both sides of the equation yields


{{{d=t*sqrt(4000)=63.24t}}}


Step 5.  ANSWER is  {{{d=t*sqrt(4000)=63.24t}}}



I hope the above steps were helpful.


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And good luck in your studies!


Respectfully,
Dr J

http://www.FreedomUniversity.TV