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Transparency 4. Click the mouse button or press the Space Bar to display the answers. Splash Screen. Example 4-3b. Objective. Find missing angle measures in quadrilaterals and classify quadrilaterals. Example 4-3b. Vocabulary. Quadrilateral. - PowerPoint PPT Presentation
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Objective
Find missing angle measures in quadrilaterals and classify
quadrilaterals
Vocabulary
Quadrilateral
A polygon that has four sides and four angles and the total of the four angles is 3600
Vocabulary
Trapezoid
A quadrilateral with exactly one pair of parallel opposite sides
Vocabulary
Parallelogram
A quadrilateral with both pairs of opposite sides parallel and congruent
Vocabulary
Rectangle
A parallelogram with four right angles
Vocabulary
Rhombus
A parallelogram with four congruent sides but does not have 900 angles
Vocabulary
Square
A parallelogram with four congruent sides and four right angles
Example 1 Find a Missing Angle Measure
Example 2 Classify Quadrilaterals
Example 3 Classify Quadrilaterals
Find the value of q in quadrilateral PQRS.
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Definition of quadrilateral states that the sum of the angles is 3600
Write equation for sum of angles of the quadrilateral
mP + mS + mR + mQ = 360
Group the known values together
Find the value of q in quadrilateral PQRS.
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Replace mP with 124
mP + mS + mR + mQ = 360
124
Replace mS with 120
124 + 120
Replace mR with 36
124 + 120 + 36
Define the variable q as the unknown (can use m Q)
124 + 120 + 36 + q
Find the value of q in quadrilateral PQRS.
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Bring down = 360
mP + mS + mR + mQ = 360
124124 + 120124 + 120 + 36124 + 120 + 36 + q124 + 120 + 36 + q = 360
Combine “like” terms
280 + q = 360
Ask “what is being done to the variable?”
The variable is being added by 280
Find the value of q in quadrilateral PQRS.
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Do the inverse on both sides of the equal sign
mP + mS + mR + mQ = 360
124124 + 120124 + 120 + 36124 + 120 + 36 + q124 + 120 + 36 + q = 360
280 + q = 360
Bring down 280
280
Subtract 280
280 - 280
Bring down + q = 360
280 - 280 + q = 360
Find the value of q in quadrilateral PQRS.
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Subtract 280
mP + mS + mR + mQ = 360
124124 + 120124 + 120 + 36124 + 120 + 36 + q124 + 120 + 36 + q = 360
280 + q = 360
280 280 - 280 280 - 280 + q = 360 280 - 280 + q = 360 - 280
Combine “like” terms0
Bring down + q =
0 + q =
Combine “like” terms
0 + q = 80
Find the value of q in quadrilateral PQRS.
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Use the Identity Property to add 0 + q
mP + mS + mR + mQ = 360
124124 + 120124 + 120 + 36124 + 120 + 36 + q124 + 120 + 36 + q = 360
280 + q = 360
280 280 - 280 280 - 280 + q = 360 280 - 280 + q = 360 - 280
0 0 + q = 0 + q = 80 q = 80 Add dimensional analysisq = 800
Answer: mQ =800
Answer: 1500
Find the value of q in quadrilateral QUAD.
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Answer: quadrilateral
Classify the quadrilateral using the name that best describes it.
No congruent sides
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No special angles
Answer: rhombus
Classify the quadrilateral using the name that best describes it.
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All sides are congruent
2 pair of sides parallel
Answer: square
Classify the quadrilateral using the name that best describes it.
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All sides are congruent
All angles are right (900)
Answer: rectangle
Classify the quadrilateral using the name that best describes it.
*
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Opposite sides congruent and parallel
All angles are right (900)
Assignment
Lesson 6:4 Classifying Quadrilaterals 4 - 23 All
