文档介绍：Perpendicular: lines, rays or segments that intersect at right angles.
Τ
Symbol for perpendicular
Τ
a
b
a
b
A
D
B
AB
BD
X
Y
A
B
XY
AB
Τ
Τ
If <B is a right angle, then AB BC
Τ
C
A
B
Can’t assume unless you have a right angle or given.
Τ
A
C
D
B
Given: AB BC
DC BC
Conclusion: <B = <C
~
Τ
Τ
Statement Reasons
AB BC
<B is a right <.
DC BC
<C is a right <.
<B = <C
Τ
Given
If 2 segments are , they form a right <.
Given.
If 2 segments are , they form a right <.
If <‘s are right <‘s, they are =.
Τ
Τ
Τ
~
~
Given: KJ KM
<JKO is 4 times as large as <MKO
Find: m<JKO
Τ
M
J
K
O
x°
4x°
Solution:
Since KJ KM, m<JKO + m<MKO = 90°.
4x + x = 90
5x = 90
x = 18
Substitute 18 for x, we find that m<JKO = 72°.
Τ
Given: EC ll x axis
CT ll y axis
Find the area of RECT
x axis
y axis
-3 -2 -1 1 2 3
321
123
C (7, 3)
T
R (-4,-2)
E
Solution:
The remaining coordinates are T = (7, -2) and E = (-4, 3). So RT = 11 and TC = 5 as shown.
Area = base times height.
A = bh
= (11)(5)
=55
The area of RECT is 55 square units.
Complementary Angles
Complementary angles are two angles whose sum is 90°.
Each of the two angles is called plement of the other.
A
B
40°
50°
<A & <B plementary.
plementary Angles
<C plementa