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H. I. K. J. Warm up (TI). Name all pairs of consecutive angles. Name all pairs of opposite vertices. Name all pairs of consecutive sides. Name all diagonals. Find the missing measure if 3 of the 4 angles below are 90, 75, and 25. Parallelograms. Unit 3 Concept 5.
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H I K J Warm up (TI) • Name all pairs of consecutive angles. • Name all pairs of opposite vertices. • Name all pairs of consecutive sides. • Name all diagonals. • Find the missing measure if 3 of the 4 angles below are 90, 75, and 25.
Parallelograms Unit 3 Concept 5
Special Quadrilaterals! • A parallelogram is a special quad with both pairs of opposite sides parallel!
NAME: FAKE Parallelograms… • Symbol F A E K
Special properties!!! • Opposite angles are congruent. • Opposite sides are congruent. • Consecutive angles are supplementary. • Diagonals bisect each other.
Examples • In KLMN, KL = 23, KN = 15, and m<K = 105. • Find LM and MN. • Find m<M. • Find m<L. 23 K L 105 15 N M
Examples • In PQRS, if PR = 32, find PL. P Q L R S
Guided Practice • Find the value of each variable in the parallelogram: 1. 2. 3. 4. 16 2a + 1 10 7 2b - 3 2x y + 2 21 52 º 4(p º +3) 4mº 135 º
More Practice… • Find the indicated measure in PQRS. • PR • ST • mSRQ • m PQR Q P 3m 2n T 12 - n 15 2xº S R 5(x+1)º
Finding the Intersection of Diagonals (Teacher Demo using Midpoint) The vertices of ABCD are A (-1,6), B (5, 6), C (3, -2), and D (-3, -2). The diagonals intersect at point P. What are the coordinates of P? A B P D C
Practice… • The vertices of ABCD are A (-4, 2), B (3, 2), C (1, -1) and D (-6, -1). The diagonals intersect at point P. What are P’s coordinates?
Theorem • A diagonal of a parallelogram separates it into two congruent triangles. R B T A
Complete Properties of Parallelograms Worksheet • Turn in for a daily grade!