$4\mathrm{.}2\mathrm{.}4.$

groupwork

Programming Challenge : Turtles Drawing Shapes

In the last exercise, you used a for$-$loop to have the turtle draw a square. Use the Active Code window below to have yertle draw the following shapes using loops. We encourage you to work in pairs.

Have yertle draw an equilateral triangle using a loop. How many times should the loop run? Remember that it ran $4$ times for a square, so how many for a triangle? What angle should you use for the turns? One way to figure this out is to notice that to complete a shape, all the exterior angles should add up to $360$ degrees. So$,$ for a square $4$x$90=360.$

Have yertle draw a pentagon using a loop. A pentagon has $5$ sides. What external angle should you use for the turns? Remember they have to add up to $360$ degrees.

Create a variable n that holds the number of sides for any polygon, and use n in your loop for the sides and to calculate the angle to turn. Can you have the loop draw a variety of shapes by just changing the value of the variable n$?$ The power of abstraction$!$ Can you draw a $9$ sided nonagon? $($Note that if the turtle runs into walls, it stays there and will mess up the shape, so you may have to move the turtle or go forward smaller amounts$).$

Use a for$-$loop to draw a triangle. Then, change it to a pentagon. Then change it to draw any polygon using a variable n that holds the number of sides. Note that the angles in the turns have to add up to $360.$ The autograder only checks one shape at a time, so comment out the code for one shape before starting on the next.