This polygon thing is all about triangles. If the polygon has 18 sides, it also has 18 central angles. 360/18 = 20. This means that each one of the triangles has a vertex angle of 20. We need to take this one triangle now and "pull" it out and isolate it cuz we only need to worry about 1, and we need to find the base measure of it for the perimeter, and the altitude of it for the apothem. It would be easiest then to separate this triangle in half and have it be a right triangle, and the vertex angle is now 10. If the vertex angle is 10 and this is a right triangle, then the 3rd angle by the triangle angle-sum theorem has to be 80. The side ACROSS from the 80 degree angle is the apothem and the info telling us that the radius is 13 now puts that 13 as the hypotenuse of our right triangle. We will use a trig identity relating this reference angle of 80 to the side across from it, "a", and the hypotenuse of 13. 
and we get that that side measures 12.8, rounded. Now we have the apothem for the formula. Now we need the base measure of the right triangle. Use cos of 80 to find it: 
ad we get the base measure of the right triangle is 2.25. But don't forget that this is only half the original triangle we pulled out, so the base of the "whole" triangle is 2.25 * 2 which is 4.5. If one side measures 4.5 and we have 18 of them, the perimeter for our formula is 81. Now let's put everything together in the formula to find the area for the polygon: 
and we find that the area is 518.4
1 cm= 4 meters model is 75 1/4 cm tall what is the actuall height
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Linear equation is the equation in which the highest power of the unknown variable is one.
The given equation the constant 2000 represents the base salary or the fixed salary of the salesman.
To find that what does 2000 represent in the given linear equation we need to know about the linear equation.
<h3>What is linear equation?</h3>Linear equation is the equation in which the highest power of the unknown variable is one.
Given information-
Total sales by salesman each month is dollars.
The total money made by the salesman each month by selling goods of dollars given by,
The above equation given in the problem is the linear equation. In this linear equation the salary of salesman depends on his sales.
The constant amount of $2000 is the fixed amount of the salesman.
The variable is the variable on which the salary of the salesman depends. Thus due to this variable the salary of the salesman changes.
Hence in the given equation the constant 2000 represents the base salary or the fixed salary of the salesman.
Learn more about the linear equation.