Expert: Paul Klarreich - 9/30/2008

Question
A wheelchair ramp should have an angle less than 8 degrees to be considered safe. A ramp at a store has a horizontal length of 12 m and a height of 150 cm. Is the ramp safe?

(I don't understand how 2 do this question b/c the length is in metres and the height is in centimetres? Do I have 2 convert one into another OR can I just figure it out easily?)

Answer
Questioner:   Jeannie
Category:  Advanced Math
Private:  No
 
Subject:  HELP
Question:  A wheelchair ramp should have an angle less than 8 degrees to be considered safe. A ramp at a store has a horizontal length of 12 m and a height of 150 cm. Is the ramp safe?

(I don't understand how 2 do this question b/c the length is in metres and the height is in centimetres? Do I have 2 convert one into another OR can I just figure it out easily?)
.........................................................................
Hi Jeannie,

Before we start: in the future, if you don't mind, please write in English instead of text-messaging.  This site does not charge by the letter. (It does not charge at all, in fact.)


You start by drawing a diagram, of course, just as in any other geometry problem.  As to the 'meters' vs 'cm', naturally, you should always make all units consistent.  Meters in one place, meters everywhere;  or centimeters here, centimeters everywhere.

Your diagram is:


         /|
       /  |
     /    | 150 cm
   /      |
 /        |
/ theta    |
------------
 1200 cm

Now just use some trigonometry to compute theta.