Page 95 - Math Course 1 (Book 2)
P. 95
Relationships in Angles
MO. 9 - L5b Key Concept
Perpendicular Lines
and Interpret Figures Vertical Angles
Words Perpendicular lines intersect to form
Vocabulary A-Z four right angles.
Let us learn some vocabulary
Perpendicular lines intersect to form
congruent adjacent angles.
Segments and rays can be perpendicular
perpendicular to lines or the other line segments and
Lines, segments, or rays that form right angles are rays.
perpendicular.
The right angle symbol in the f gure
Y indicates that the lines are
X perpendicular.
Symbols ⊥ is read is perpendicular to.
Y
X
W Z
↔ ↔
WZ ⊥ WY
Symbol ⊥ is read is perpendicular to.
W Z
↔ ↔
Let’s Begin WZ ⊥ WY
Perpendicular Lines
Examples
↔ ↔
Algebra If KO ⊥ HM, then m∠KJH = 90. To f nd x, use ∠KJI
↔ ↔
Find x so that KO ⊥ HM.
and ∠IJH.
m∠KJH = m∠KJI + m∠IJH Sum of parts = whole
90 = (3x + 6) + 9x Substitution
90 = 12x + 6 Add.
Subtract 6 from each
84 = 12x
side.
7 = x Divide each side by 12.
Answer x = 7
87
