Angles of a Triangle The three angles of a triangle have a sum equal to 180 degrees. A + B + C = 180 B A C
Mar 16, 2016
Angles of a Triangle
The three angles of a triangle have a sum equal to 180 degrees.
A + B + C = 180
B
A
C
Example
A triangle has three angles , A , B and C.
Angle B is 10 less than two times angle A.
Angle C is 10 more than three times angle
A. Find the measure of each angle.
Supplementary Angles
Angles A and B have a sum of 180 degrees.A + B = 180 A = 180 – B B = 180 - A
BA
Complementary Angles
Angles A and B have a sum of 90 degrees.A + B = 90 A = 90 - B
AB
Example
Find the angle such that its supplement
added with its complement equals 230
degrees.
RectanglesL
W
Area = (Length)(Width) = LW
Perimeter = 2W + 2L
Note: These formulas are just algebraic expressions. If we know the values for the variables, then we can Evaluate the area and perimeter.
Example7 ft
3ft
Find the area and perimeter.
A = LW = (7)(3) = 21ft²
P = 2W + 2L = 2(3) + 2(7) = 6 +14 = 20 ft
Perimeter
16 m
W
Find the width if the perimeter is 56 meters.
Triangles
Base = b
Height=h
Area = bh 21
Triangle
Area =48 cm²
12cm
Find the height , h
Circles
14.3
Radius = r
Area = r²
Circumference = 2 r
Circles
4 meters
Find the approximate area and circumference.
Swimming Pool20ft
14ft
5ft
7ft
Volume of a Rectangular Solid
LW
H
Volume = LWH
Volume of a Sphere
Radius=r
³34 rV
Find the volume if the radius = 3 meters
Vertical Angles are formed when two lines are intersected.
ABC
D
Angle A = Angle D and
Angle C = Angle B
Find the measure of each Angle
(10x+15)
(12x-3)
Find the measure of each angle
(3x +10)(5x+10)
Solving Formulas for one variable
3259
CF
If C = 25, find F
Solve the formula for C
If F = 82, find C
Solve each formula for the stated variable.
a)
b) P = 2W + 2L , for W
c) Ax + By = C , for y
d) A = p + prt , for r
bHA21
For b