Aim #1: How do we find perimeter and area in the Cartesian Plane?
CC Geometry R
Do Now: Find the area of the shaded region.
a)
4
b)
3
1
2
6
­1
­4
­3
2
­2
3
­2
­3
­4
1) Plot the points O (0,0), A (5,2) and B (3,4)
a) Find the perimeter of ΔOAB to the nearest
hundredth.
b) Find the area of ΔOAB using decomposition. Start by enclosing the triangle
with a rectangle.
c) When is it easier to apply the area formula and not us decomposition?
4
2) Given the triangle, find the area using decomposition.
3) Find the area of the triangles with vertices listed by using decomposition:
a) A(0,4)
B (5,6)
C (4,1)
b) A(-5,5)
B (3,-3)
C (-2,6)
3) Find the area quadrilateral ABCD with vertices listed by using decomposition:
A(-1,2)
B(1,-6)
C(6,-4)
D(6,6)
b) Decompose ABCD internally.
4) Given rectangle ABCD,
a. Identify the vertices.
b. Find the exact perimeter using the
distance formula.
c. Find the area using the area formula.
d. Verify your answer from (c) using decomposition.
5) Calculate the area and perimeter (nearest hundredth) of quadrilateral ABCD .
6) Find the perimeter (to the nearest hundredth) and the area of the
quadrilateral with vertices A(-3,4), B(4,6), C(2,-3), and D(-4,-4).
7) Find the area of the pentagon with vertices A(5,8), B(4,-3), C(-1,-2), D(-2,4),
and E(2,6).
A
E
D
C
B
8) Find the area and perimeter of the hexagon shown.
Let's Sum it Up!
To find the perimeter of a triangle, use the distance formula to find the length of
each segment and add the distances together.
To find the area of a polygon , you can use the decomposition method.