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