Chapter 5 Section 5.5 Inequalities in a triangle
-3 x < > -x -2 < x Don’t forget to change it! -2x 3 < 2x < 2x 22 6 < x6 < x
Compare Sides to Order Angles Theorem Theorem 5.10 If one side of a triangle is longer than another side, then the angle opposite the longer side is larger than the angle opposite the shorter side. A B C CB > CA > AB m A > m B > m C
Compare Angles to Order Sides Theorem Theorem 5.11 If one Angle of a triangle is larger than another angle, then the side opposite the larger angle is longer than the side opposite the smaller angle. Q P R QR > PR > PQ m P > m Q > m R
m M > m K > m L KL > LM > KM
m M > m O > m N ON > MN > OM
m B > m A > m C AC > BC> AB
m F > m E > m G EG > GF > EF
m J > m I > m H HI > HJ > IJ
m K > m L > m M LM > KM > KL
In ABC CB > AB > AC In CBD BD > CD > CB Thus BD > CD > CB > AB > AC
In LKM LM > KL > KM In LMN MN > LN > LM Thus MN > LN > LM > LN > LM
Theorem Theorem 5.12 Exterior Angle Inequality The measure of an exterior angle of a triangle is greater than the measure of the two nonadjacent interior angles. m TQR > m R TQR is an exterior angle of QRP Inequalities in a triangle Q P R T And m TQR > m P
Theorem Theorem 5.13 Triangle Inequality The sum of the lengths of any two sides of a triangle is greater than the length of the third side. AB + BC > AC AB + AC > BC BC + AC > AB Inequalities in a triangle
The sum of any two sides must be greater than the third side! XZ + YZ > XY XZ + XY > YZ YZ + XY > XZ > XY 5 > XY 2 + XY > 3 XY > XY > 2 XY > -1 5 > XY > 1
The sum of any two sides must be greater than the third side! XZ + YZ > XY XZ + XY > YZ YZ + XY > XZ > XY 18 > XY 8 + XY > 10 XY > XY > 8 XY > > XY > 2
CC AF DS x > x 60 + x > > x x > -20 x + 40 > 60 x > > x > 20 No, the distance must be less than 100 miles