Transcript Lesson 6.4

𝑚∠𝐷𝐶𝑂 ≅ m∠BOC ≅ 𝑚∠𝐷𝐴𝑂 ≅ 𝑚∠𝐵𝐴𝑂
𝑚∠𝐴𝐷𝑂 ≅ 𝑚∠𝐶𝐷𝑂 ≅ 𝑚∠𝐶𝐵𝑂 ≅ 𝑚∠𝐴𝐵𝑂
𝑚∠𝐷𝑂𝐴 ≅ 𝑚∠𝐷𝑂𝐶 ≅ 𝑚∠𝐵𝑂𝐴 ≅ 𝑚∠𝐵𝑂𝐶 = 90
𝑚∠1 = 78
𝑚∠2 = 90
𝑚∠3 = 180 − 90 − 78 = 12
𝐴𝐶 = 𝐷𝐵
2𝑦 + 4 = 6𝑦 − 5
−6𝑦 − 4 − 6y − 4
−4𝑦 = −9
−4
−4
9
𝑦=
4
9
17
1
𝐹𝐷 = GE = 2
+4=
=8
4
2
2
Theorem 6-12: If one diagonal of a parallelogram
bisects two angles of the parallelogram, then the
parallelogram is a rhombus.
Theorem 6-13: If the diagonals of a parallelogram
are perpendicular, then the parallelogram is a
rhombus.
Theorem 6-14: If the diagonals of a parallelogram
are congruent, then the parallelogram is a
rectangle.
• Pg. 315-317 #1-21 and 48-50