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EOC Review #5 Thursday. Given: Endpoint (2, 3); Midpoint (3, -4) Find the missing endpoint. EOC REVIEW QUIZ TOMORROW . Honors H.W. #23 pg. 246. #2-32 and 38 (even). H.W. QUESTIONS?.
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EOC Review #5Thursday • Given: Endpoint (2, 3); Midpoint (3, -4) Find the missing endpoint. EOC REVIEW QUIZ TOMORROW
Honors H.W. #23pg. 246 #2-32 and 38 (even)
38.) In GHJ, K(2,3) is the midpoint of GH, L(4,1) is the midpoint of HJ, and M(6,2) is the midpoint of GJ.
Bisectors in TrianglesToolkit #5.2 Today’s Goal: To use properties of perpendicular bisectors and angle bisectors.
Perpendicular Bisector: equidistant from the endpoints of a segment (cuts SEGMENT in two EQUAL parts), and makes a RIGHT ANGLE with that segment. • When three perpendicular bisectors meet, that POINT is called the CIRCUMCENTER.
Find the set of points on the map of D.C. that are equidistant from the Jefferson Memorial and the White House.
Ex.1: CD is the perpendicular bisector of AB. Find CA and DB.
Angle Bisector: equidistant from the sides of a triangle – cuts an ANGLE into TWO EQUAL parts. • When three angle bisectors meet, the POINT is called the INCENTER.
Ex.2(b):Check Understanding • According to the diagram, how far is K from EH? From ED? • What can you conclude about EK? • Find the value of x. • Find mDEH.
In-Class Practice (Part I)Geometry Book • Pg. 251 • #’s 1-4, 6-11
AC is the bis. of BD 15 18 8 x = 12, JK = JM = 17 y = 3, ST = TU = 15 HL is the bis. of JHG. y = 9, mFHL=54, mKHL=54 27 Point E is on the bisector of KHF. Solutions – Part I
In-Class Practice (Part II)Geometry Book • Pg. 252 • #’s 12-15, 18-25
5 10 10 Isosceles 12 4 4 16 5 10 7 14 Solutions – Part II
In-Class Practice (Part III)Geometry Book • Pg. 252 • #’s 28-30 (Draw picture!)
Solutions – Part III • No, A is not equidistant from the sides of X • Yes, AX bisects TXR • Yes, A is equidistant from the side of X.
Bisectors & GraphingCh. 5.2 Extension Today’s Goal(s) To investigate perpendicular and angle bisectors on the coordinate plane.
Example:Given points A(1,3), B(5,1), and C(4,4), does C lie on the bisector of AB? • Plot points first! • Then determine whether AC = BC.
Concurrent Lines, Medians, and AltitudesToolkit 5.3 Today’s Goal: To identify properties of medians and altitudes of a triangle.
STOP and THINK!What does concurrent mean? • When three or more lines intersect in one point, the point at which they intersect is the point of concurrency.
Median of a triangle: a segment that connects a VERTEX to the MIDPOINT of the opposite side. • When three medians meet, the POINT is called the CENTROID.
The medians of a triangle are concurrent at a point where the distance from the point to the vertex is TWICE the distance from the point to the side.
D is the centroid of ABC and DE = 6. Find BE. Ex.1(a): Finding Lengths of Medians
Ex.1(b): Finding Lengths of Medians You Try… M is the centroid of WDR, and WM = 16. Find WX.
Altitude of a triangle: a segment that is PERPENDICULAR to a side, and connects a VERTEX to the opposite side. • When three altitudes meet, the POINT is called the ORTHOCENTER.
4 Points of Concurrency SummaryHelpful Hint! CM PB IN AB C M O A
Other Uses!Perpendicular Bisectors Pt. of Concurrency: The circle is circumscribed about ABC.
Other Uses!Angle Bisectors Pt. of Concurrency: The circle is inscribed in ABC.
Other Uses!Medians Pt. of Concurrency: “Balance Point” Also called the center of gravity of a triangle because it is the point where a triangular shape will balance.
Other Uses!Altitudes Pt. of Concurrency: “Heights” of a triangle.
Ex.2(a.): Find the center of the circle that circumscribes XYZ.
Ex.2(b.): Find the center of the circle that circumscribes XYZ. You Try… X(0,0), Y(0,6), Z(4,0)