Logo AreaDate: 03/26/2003 at 21:06:37 From: Cheyenne Subject: Finding the area in square units How do we find the area in square units following the Logo command? Logo command fd 40 rt 90 fd20 Date: 03/26/2003 at 23:28:07 From: Doctor Ian Subject: Re: Finding the area in square units Hi Cheyenne, Let's simulate what the turtle would do to find out. Let's assume it starts out facing to the right: O> We tell it to go forward 40 units: 40 . . . . . . . . . . O> then turn right 90 degrees, 40 . . . . . . . . . . O v then go forward 20 units, 40 . . . . . . . . . . . . . . 20 . O v Now, in one sense, there's no 'area' yet, because the turtle hasn't yet returned to the starting point. Does that make sense? But it _might_ go back to complete a rectangle: ^ 40 O . . . . . . . . . . . . . . . . 20 . . . . . . . . . . . . . In this case, the area would be the width times the height, area(rectangle) = width * height = 40 * 20 = 800 But it might go straight back, to complete a triangle: ^ 40 O . . . . . . . . . . . . . . . . 20 . . . In this case, the area would be half the area of the rectangle, area(triangle) = (1/2) * base * height = (1/2) * 40 * 20 = 400 Or it might wander all over the place! ^ 40 O . . . . . . . . . . . . . . . . . 20 . . . . . . . . . . . . . . Do you see why you need to know how the turtle gets back to where it started before you can figure out the area? If you're not completely comfortable with the idea of area yet, you might want to take a look at this: Area and Perimeter http://mathforum.org/library/drmath/view/57652.html Does this help? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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