38. Use the diagram below.

    

    1. What is the most precise classification of ABCD?
    2. What is the most precise classification of EFGH?
    3. Are ABCD and EFGH congruent? Explain.

C Challenge

39. Coordinate Geometry The diagonals of quadrilateral EFGH intersect at D( − 1 , 4 negative 1 comma 4 ). EFGH has vertices at E(2, 7) and F( − 3 , negative 3 comma 5). What must be the coordinates of G and H to ensure that EFGH is a parallelogram?

The endpoints of A B ¯ eh b bar are A( – 3 , en dash 3 comma 5) and B(9, 15). Find the coordinates of the points that divide A B ¯ eh b bar into the given number of congruent segments.

40. 4
41. 6
42. 10
43. 50
44. n

Standardized Test Prep

SAT/ACT

45. K( − 3 , negative 3 comma 0), I(0, 2), and T(3, 0) are three vertices of a kite. Which point could be the fourth vertex?
    1. E(0, 5)
    2. E(0, 0)
    3. E(0, − 2 negative 2 )
    4. E(0, − 10 negative 10 )

46. In the diagram, lines l and m are parallel. What is the value of x?

    

    6. 5
    7. 12
    8. 13
    9. 25

47. In the diagram, which segment is shortest?

    

    1. P S ¯ p s bar
    2. P R ¯ p r bar
    3. P Q ¯ p q bar
    4. Q R ¯ q r bar

Short Response

48. A( − 3 , negative 3 comma 1), B ( − 1 , − 2 ) , b open negative 1 comma negative 2 close comma and C(2, 1) are three vertices of quadrilateral ABCD. Could ABCD be a rectangle? Explain.

Mixed Review

See Lesson 6-6.

49. Algebra Find the measure of each angle and the value of x in the isosceles trapezoid.

    

See Lesson 5-3.

Find the circumcenter of Δ A B C . cap delta eh b c .

50. A(1, 1), B(5, 3), C(5, 1)
51. A( − 5 , negative 5 comma 0), B ( − 1 , − 8 b open negative 1 comma negative 8 ), C( − 1 , negative 1 comma 0)

Get Ready! To prepare for Lesson 6-8, do Exercises 52–54.

See Lesson 3-7.

Find the slope of X Y ¯ . x y bar , .

52. X(0, a), Y ( − a , 2 a ) y open negative eh comma 2 eh close
53. X( − a , negative eh comma b), Y(a, b)
54. X(a, 0), Y(c + d, b)

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