Question 167952
Avoiding a collision. A car is traveling on a road that is perpendicular to a
 railroad track. When the car is 30 meters from the crossing, the car’s new
 collision detector warns the driver that there is a train 50 meters from the
 car and heading toward the same crossing. How far is the train from the crossing?
:
This is a right triangle problem: a^2 + b^2 = c^2
:
Let a = 30 (car dist from the crossing)
Let c = 50 (diagonal or hypotenuse) detector reading
Let b = dist train is from the crossing
:
30^2 + b^2 = 50^2
:
900 + b^2 = 2500
:
b^2 = 2500 - 900
:
b^2 = 1600
b = {{{sqrt(1600)}}}
b = 40 meters, train is from the crossing 
;
:
Check solution on a calc; enter {{{sqrt(30^2 + 40^2)}}} = 50