Transcript Instructional Slide Show

Geometry
Mrs. Cutbirth

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a ≈ __________
s = 107.5 cm
A = 19,887.5 cm2
Answer
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P ≈ ___________
a = 38.6 mm
A = 4940.8 mm2
Answer
Exit
Regular n-gon: a = 9.6 cm and A = 302.4 cm2,
P ≈ _______
Answer
Exit
Find the perimeter of a regular polygon if
a = 9m and A ≈ 259.2 m2
Answer
Exit
Find the shaded area of AORNGIS of the regular
octagon ROADSIGN. The apothem measures
about 20 cm. Segment GI measures about 16.6
cm.
G
I
N
S
R
D
O
Answer
A
Exit
An interior designer created the kitchen plan shown.
The countertop will be constructed of colored
concrete. What is its total surface area? If concrete
countertops 1.5 inches thick cost $85 per square
foot, what will be the total cost of this countertop?
Answer
Exit
Find the sum of the interior angles in the
polygon. Then find the value of p.
 Sum of interior angles = _______
 p = _______
Answer
Exit
The measure of an exterior angle of a regular
octagon is x + 7. Find x and the measure of
each exterior angle of the octagon.
Answer
Exit
Suppose a regular polygon has n sides. Write an
expression to describe each of the following
quantities for that regular polygon.
a)
the sum of the measures of the interior angles
b)
the measure of each interior angle
c)
d)
the sum of the measures of the exterior angles (one at each
vertex)
the measure of each exterior angle.
Answer
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Find the area of the trapezoid. A = ___________
Answer
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Find the area. A=___________
28 cm
Answer
22 cm
Exit
In the figure at the right, quadrilateral WXYZ is a
trapezoid.
a)
b)
Explain why ∆WXY and ∆XYZ have the same area (Hint:
Consider XY as the base of both triangles.)
Use the answer in part a and the Area Addition Postulate to
explain why ∆WXR and ∆RYZ have the same area.
Answer
Exit
Your test is tomorrow. It will cover all of the
material from chapter 10.
Exit
a ≈ __________
s = 107.5 cm
A = 19,887.5 cm2
𝐴=
1
𝑎𝑠𝑛
2
Plug in for A and s, then
solve your equation.
Exit
P ≈ ___________
a = 38.6 mm
A = 4940.8 mm2
𝐴=
1
𝑎𝑃
2
Plug in for A and a, then
solve your equation.
Exit
Regular n-gon: a = 9.6 cm and A = 302.4 cm2,
P ≈ _______
𝐴=
1
𝑎𝑃
2
Plug in for A and a, then
solve your equation.
Exit
Find the perimeter of a regular polygon if
a = 9m and A ≈ 259.2 m2
𝐴=
1
𝑎𝑃
2
Plug in for A and a, then
solve your equation.
Exit
Find the shaded area of AORNGIS of the regular
octagon ROADSIGN. The apothem measures
about 20 cm. Segment GI measures about 16.6
cm.
G
I
Find the area of the regular polygon
1
using the formula, 𝐴 = 2 𝑎𝑠𝑛.
a = apothem
s = side length (GI)
n = number of sides
Then multiply that value by the
fraction of the polygon that is shaded.
What fraction of the total sides is
shaded?
N
S
R
D
O
A
Exit
1. The shape is made up of
two rectangles and one
regular octagon.
3. To calculate the
cost you will need to
know how many
square feet you have.
If your area is in in2,
you will need to do a
conversion. There are
144 in2 in 1ft2.
24 in
2. The apothem is the
distance from the
center to the side.
Exit
Find the sum of the interior angles in the
polygon. Then find the value of p.
 Sum of interior angles = _______
 p = _______
𝑠𝑢𝑚 = 𝑛 − 2 180
Where n = the number of sides
To find p, set up and equation.
Add up all of the angles and set
them equal to the sum you found.
Exit
The measure of an exterior angle of a regular
octagon is x + 7. Find x and the measure of
each exterior angle of the octagon.
The sum of the exterior angles is
360o. To find one exterior angle,
divide the sum by the number of
sides. To calculate x you can then
set up an equation.
Exit
Find the area of the trapezoid. A = ___________
1
𝐴 = 2 ℎ(𝑏1 + 𝑏2 )
h= perpendicular height
𝑏1 and 𝑏2 are the parallel bases
Exit
Find the area. A=___________
1
A = 2 𝑏ℎ
The b and h must be perpendicular.
28 cm
22 cm
Exit
a=
2
61 𝑐𝑚
3
𝑜𝑟 61. 6𝑐𝑚
Exit
P = 256mm
Exit
P = 63cm
Exit
P = 57.6 m
Exit
A = 996 cm2
Exit
A = 50 ft2 or 7200 in2
Cost = $4250
Exit
Sum = 900
p = 50
Exit
x = 38
45o
Exit
a)
b)
(n – 2)180
𝑛−2 180
𝑛
c)
360
d)
360
𝑛
Exit
A = 297 in2
Exit
A = 308 cm2
Exit
a)
b)
The area formula for a triangle is A = ½ bh.
Both triangles share the same base and
have the same height.
Both triangles have the same area. If you
subtract the same area from each triangle,
then the remaining amount on each triangle
will be the same.
Exit