# Geometry Notes – Lesson 6.2 Name _________________________________

```Notes – Lesson 6.2
Geometry
Name _________________________________
Theorem 6.1: __________________________________ sides of a parallelogram are ______________________________.
If ABCD is a parallelogram, then
Complete the proof.
Consecutive Angles:
Definition: Angles that share a ____________ and are ______________________________ (add up to 180 0)
From the picture:
 A +  B = _____________
 B + __________ = 180o
Examples:

1 = _________
 1 = _______,  2 = _______,  3 = ________
 1 = _______,  2 = _______,  3 = ________
Theorem 6.2: __________________________ angles of a parallelogram are _______________________.
Examples:
 1 = _______,  2 = _______,  3 = ________  1 = _______,  2 = _______,  3 = _______  1 = _______,  2 = _______,  3 = _______
Proving a Rectangle and a Square.
Rectangle – a parallelogram with 4 right angles.
To Prove:
Opposite sides are _______________
Four 90o angles
Square – a parallelogram with 4 congruent sides and 4 right angles.
To Prove:
Opposite sides are ______________
All sides are ______________
Four 90o angles
\Example. Prove this figure is a rectangle.
R(-2, -3), S(4, 0), T(3, 2), V(-3, -1)
Theorem 6.3: The _____________________________ of a parallelogram _______________ each other.
ABCD is a parallelogram. Therefore:
BO = ___________
AO = ___________
Examples.
Theorem 6.4: If three (or more) ______________ _________________ cut off congruent
segments on one _________________, then they cut off congruent segments
on every transversal.
Using Algebra with the Theorems.
IK = 35
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