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The Quadrilateral Family Tree. Wednesday 1/5/11 – Thursday 1/6/11. SPECIAL PARALLELOGRAMS. Special Parallelograms. Rectangles, rhombuses, and squares. Rectangles. Rectangle. A quadrilateral with four right angles. Rectangle. Has all the properties of a parallelogram. Quadrilateral.
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The Quadrilateral Family Tree Wednesday 1/5/11 – Thursday 1/6/11 SPECIAL PARALLELOGRAMS
Special Parallelograms Rectangles, rhombuses, and squares
Rectangle • A quadrilateral with four right angles
Rectangle • Has all the properties of a parallelogram
Quadrilateral 1. Four-sided polygon Parallelogram 1. 2. Opposite angles are congruent 3. Diagonals bisect each other 4. Consecutive angles are supp. RECTANGLE 1. 1. 1. Four right angles 2. 2. 3. 2. All properties above 3. 4. 3. Square 1. 2. 1. 2. 1. Opposite sides are congruent 3.
Rectangle • What should be true about the overlapping triangles formed by the diagonals?
Rectangle • What should be true about the overlapping triangles formed by the diagonals?
Rectangle • The triangles are congruent by SAS since opposite sides of a parallelogram are congruent
Rectangle • So the diagonals in a rectangle must be congruent by CPCTC
Quadrilateral 1. Four-sided polygon Parallelogram 1. 2. Opposite angles are congruent 3. Diagonals bisect each other 4. Consecutive angles are supp. RECTANGLE 1. 1. 1. Four right angles 2. 2. 3. 2. All properties above 3. 4. 3. Diagonals are congruent Square 1. 2. 1. 2. 1. Opposite sides are congruent 3.
diags. bisect each other Example 1: Craft Application A woodworker constructs a rectangular picture frame so that JK = 50 cm and JL = 86 cm. Find HM. Rect. diags. KM = JL = 86
Check It Out! Example 1a Carpentry The rectangular gate has diagonal braces. Find HJ. Rect. diags. HJ = GK = 48
Check It Out! Example 1b Carpentry The rectangular gate has diagonal braces. Find HK. Rect. diags. Rect. diagonals bisect each other JL = LG JG = 2JL = 2(30.8) = 61.6
Rhombus • A quadrilateral with four congruent sides
Rhombus • Also has all the properties of a parallelogram
Quadrilateral 1. Four-sided polygon Parallelogram 1. 2. Opposite angles are congruent 3. Diagonals bisect each other 4. Consecutive angles are supp. RHOMBUS RECTANGLE 1. 1. Four congruent sides 1. Four right angles 2. All properties above 2. 3. 2. All properties above 3. 4. 3. Diagonals are congruent Square 1. 2. 1. 2. 1. Opposite sides are congruent 3.
Rhombus • What kind of triangles are formed by a diagonal?
Rhombus • What kind of triangles are formed by a diagonal?
Rhombus • What kind of triangles are formed by a diagonal?
Rhombus • Each diagonal bisects a pair of opposite angles
Rhombus • Each diagonal bisects a pair of opposite angles
Quadrilateral 1. Four-sided polygon Parallelogram 1. 2. Opposite angles are congruent 3. Diagonals bisect each other 4. Consecutive angles are supp. RHOMBUS 1. Four congruent sides RECTANGLE 1. 2. All properties above 1. Four right angles 2. 3. Diagonals bisect opposite angles 2. All properties above 3. 3. Diagonals are congruent 4. Square 1. 2. 1. 2. 1. Opposite sides are congruent 3.
Rhombus • What should be true about angles 1 and 2? 2 1
Rhombus • What would the angle measures have to be? 2 1
Rhombus • What would the angle measures have to be?
Quadrilateral 1. Four-sided polygon Parallelogram 1. 2. Opposite angles are congruent 3. Diagonals bisect each other 4. Consecutive angles are supp. RHOMBUS 1. Four congruent sides RECTANGLE 1. 2. All properties above 1. Four right angles 2. 3. Diagonals bisect opposite angles 2. All properties above 3. 3. Diagonals are congruent 4. Diagonals are Square 1. 2. 1. 2. 1. Opposite sides are congruent 3.
Example 2A: Using Properties of Rhombuses to Find Measures TVWX is a rhombus. Find TV. WV = XT 13b – 9=3b + 4 10b =13 b =1.3 TV = XT TV =3b + 4 TV =3(1.3)+ 4 = 7.9
Example 2B: Using Properties of Rhombuses to Find Measures TVWX is a rhombus. Find mVTZ. mVZT =90° Rhombus diag. 14a + 20=90° a=5 mVTZ =mZTX mVTZ =(5a – 5)° mVTZ =[5(5) – 5)]° = 20°
Check It Out! Example 2a CDFG is a rhombus. Find CD. CG = GF Def. of rhombus 5a =3a + 17 a =8.5 GF = 3a + 17=42.5 CD = GF CD = 42.5
Check It Out! Example 2b CDFG is a rhombus. Find mGCH. mGCD = (b + 3)° and mCDF = (6b – 40)° Def. of rhombus mGCD + mCDF = 180° b + 3 + 6b –40 = 180° 7b = 217° b = 31°
Check It Out! Example 2b Continued CDFG is a rhombus. Find mGCH. mGCD = (b + 3)° and mCDF = (6b – 40)° mGCH + mHCD = mGCD Rhombus each diag. bisects opp. s 2mGCH = mGCD Substitute. 2mGCH = (b + 3) Substitute. 2mGCH = (31 + 3) Simplify and divide both sides by 2. mGCH = 17°
Square • A quadrilateral with four right angles (like a rectangle) and four congruent sides (like a rhombus)
Square • So a square has all the properties of both a rectangle and a rhombus
Quadrilateral 1. Four-sided polygon Parallelogram 1. 2. Opposite angles are congruent 3. Diagonals bisect each other 4. Consecutive angles are supp. Rhombus 1. Four congruent sides Rectangle 1. 2. All properties above 1. Four right angles 2. 3. Diagonals bisect opposite angles 2. All properties above 3. SQUARE 3. Diagonals are congruent 4. Diagonals are 1. All properties of a rectangle 1. 2. 1. Opposite sides are congruent 3. 2. All properties of a rhombus
Parallelograms Rectangles Rhombuses Squares
Quadrilateral 1. Four-sided polygon Kite TRAPEZOID 1. PARALLELOGRAM 1. Opposite sides are congruent 1. 2. 2. Opposite angles are congruent 3. 3. Diagonals bisect each other 4. Consecutive angles are supplementary Isosceles Trapezoid Rhombus 1. Rectangle 1. Properties of a parallelogram 1. All properties of a parallelogram 2. All sides are congruent 2. 3. Diagonals are perpendicular 2. Four right angles 3. 4. Diagonals bisect opposite angles 3. Diagonals are congruent Square 1. Properties of a rectangle 2. Properties of a rhombus