Idiot\'s Guides Basic Math and Pre-Algebra

Check Point Answers 317

27. The area of an octagon with a perimeter of 40 inches and an apothem of 5 inches is

A^1 ap

2

1

2

 5 40 100 square inches.

28. The area of a regular decagon in which each of the 10 sides measure 2 meters and the apothem is

1.5 meters is Aap

1

2

1

2

 1.5 20 15  square meters.

If the perimeter of a regular hexagon is 42 inches and its area is 84 square inches, its apothem is
4 inches.

A regular pentagon with an area of 1,080 square inches and an apothem of 18 inches has a
perimeter of 120 inches. Each side is 24 inches.

Chapter 15

1. An arc less than half a circle is a minor arc.


2. The distance from the center point to any point on the circle is called the radius.


3. Two circles with the same center are concentric circles.


4. If two circles touch each other at just one point, the circles are tangent.


5. An arc that is exactly half the circle is called a semicircle.


6. m’TOP = 48r


7. m’MAN =

1

2 (78r) = 39r

8. m’SIT =

1

2 (36r) = 18r

9. ’ITS is inscribed in a semicircle. m’ITS = 90r.

Aap

a

a

a

1

2

84 1

2

42

84 21

4



      



Aap

p

p

p

1

2

1080 1

2

18

1080 9

120