area in the amount of space inside an enclosed region. area of rectangle = base x height base =10...
TRANSCRIPT
Area of Parallelograms and Triangles
Area in the amount of space inside an enclosed region.
Area of Rectangle = base x height
Area of a Rectangle
Base =10
Height = 6
Area = (10)(6) = 60 square units
A parallelogram has the same area of a rectangle because if you cut off part of a parallelogram and move it to the other side it looks like a rectangle.
Area for a Parallelogram = Base x Height
Area of a Parallelogram
Finding the Area of a Parallelogram
55
8
8
4
The Base and Height of a figure always made a right angle.
Area of the parallelogram = base x height
= 8 x 4
= 32 square units
Another parallelogram
6
6
8
7
8
Remember the Base and Height of a figure always made a right angle.
Area Parallelogram = base x height = 6 x 7 = 42 square units
The Area of a triangle = ½ x (Base x Height) or 1/2bh
WHY?
Answer: Because every triangle is actually ½ of a parallelogram or a rectangle.
Finding the Area of a Triangle
The height of this triangle is 5.Area = ½ b h
= ½ (8) (5) = 20 square units
Sometimes the height of a polygon is outside of figure
10 6 5
8 3.4
Step 1: Graph y = x+2, y=2, x=6
Step 2: Count the length of the base and height
Step 3: Calculate the area of the triangleArea = ½ bh = ½ (6)(6) = 18 square units
Find the area of the shape enclosed by the lines: y = x+2, y=2, x=6
6
6
Step 1: Plot the pointsStep 2: Connect the dots
Step 3: Count out the base and height
Step 4: Find the AreaArea = b h = (7)(4) = 28 square units
Find the area of polygon with the given vertices: E(1,1), F(4,5), G(11,5), H(8,1)
E
F G
H
4
7
Regular Geometry:Pg 351 (1-7 all, 11-13 all, 25,27, 36-42 even)
Honors Geometry - 3 more slidesPg 351 (2-24 even, 25,27, 36-42 even, 44,45)
Homework
The trick to this problem is that there are two ways to find the area of this parallelogram:
A = (10)(x) = (8)(6) 10x = 48
x = 4.8
Find x.10
6
x8
A triangle has a height of 12 cm and an area of 48 cm2 Find the length of the base.
Area of Triangle = ½ b h48 = ½ b (12)48 = 6b 8 = base
Working backwards
A parallelogram has an area of 270 square cm. The base and height have a ratio of 5:6 respectively. Find the base and the height.
Area = b h 270 = (5x)(6x) 270 = 30x2
9 = x2
3 = x
base = 5(3) = 15 and height = 6(3) = 18
Working backwards
6x
5x