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Warm Up (On Separate Sheet & Pass Back Papers) Solve for x . 1. 16 x – 3 = 12 x + 13 2. 2 x – 4 = 90 ABCD is a parallelogram. Find each measure. 3. CD 4. m ïƒ C. 4. 47. 104°. 14. 6-4. Properties of Special Parallelograms. Holt Geometry.
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Warm Up(On Separate Sheet & Pass Back Papers) Solve for x. 1.16x – 3 = 12x + 13 2. 2x – 4 = 90 ABCD is a parallelogram. Find each measure. 3.CD4. mC 4 47 104° 14
6-4 Properties of Special Parallelograms Holt Geometry
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 Def. of segs. Substitute and simplify.
Example 2B: Using Properties of Rhombuses to Find Measures TVWX is a rhombus. Find a. mVZT =90° Rhombus diag. Substitute 14a + 20 for mVTZ. 14a + 20=90° Subtract 20 from both sides and divide both sides by 14. a=5
A square is a quadrilateral with four right angles and four congruent sides.
Example 3: Verifying Properties of Squares Show that the diagonals of square EFGH are congruent perpendicular bisectors of each other.
Step 1 Show that EG and FH are congruent. Since EG = FH, Example 3 Continued
Step 2 Show that EG and FH are perpendicular. Since , Example 3 Continued
Step 3 Show that EG and FH are bisect each other. Since EG and FH have the same midpoint, they bisect each other. Example 3 Continued The diagonals are congruent perpendicular bisectors of each other.
6-5 Conditions for Special Parallelograms Holt Geometry
A manufacture builds a mold for a desktop so that , , and mABC = 90°. Why must ABCD be a rectangle? Both pairs of opposites sides of ABCD are congruent, so ABCD is a . Since mABC = 90°, one angle ABCD is a right angle. ABCD is a rectangle by Theorem 6-5-1. Example 1: Carpentry Application
Example 2A: Applying Conditions for Special Parallelograms Determine if the conclusion is valid. If not, tell what additional information is needed to make it valid. Given: Conclusion: EFGH is a rhombus. The conclusion is not valid. By Theorem 6-5-3, if one pair of consecutive sides of a parallelogram are congruent, then the parallelogram is a rhombus. By Theorem 6-5-4, if the diagonals of a parallelogram are perpendicular, then the parallelogram is a rhombus. To apply either theorem, you must first know that ABCD is a parallelogram.
Example 3B: Identifying Special Parallelograms in the Coordinate Plane Use the diagonals to determine whether a parallelogram with the given vertices is a rectangle, rhombus, or square. Give all the names that apply. W(0, 1), X(4, 2), Y(3, –2), Z(–1, –3) Step 1 Graph WXYZ.
Since , WXYZ is not a rectangle. Example 3B Continued Step 2 Find WY and XZ to determine is WXYZ is a rectangle. Thus WXYZ is not a square.
Since (–1)(1) = –1, , PQRS is a rhombus. Example 3B Continued Step 3 Determine if WXYZ is a rhombus.
Lesson Quiz: Part I 1. Given that AB = BC = CD = DA, what additional information is needed to conclude that ABCD is a square?
Lesson Quiz: Part I A slab of concrete is poured with diagonal spacers. In rectangle CNRT, CN = 35 ft, and NT = 58 ft. Find each length. 1.TR2.CE 35 ft 29 ft
Lesson Quiz: Part II PQRS is a rhombus. Find each measure. 3.QP4. mQRP 42 51°
Lesson Quiz: Part III 5. The vertices of square ABCD are A(1, 3), B(3, 2), C(4, 4), and D(2, 5). Show that its diagonals are congruent perpendicular bisectors of each other.
6.Given:ABCD is a rhombus. Prove: Lesson Quiz: Part IV
Warm-Up A slab of concrete is poured with diagonal spacers. In rectangle CNRT, CN = 35 ft, and NT = 58 ft. Find each length. 1.TR2.CE 35 ft 29 ft