Exercises 18 and 19 are based on a theorem ( not stated) that is the converse of Theorem 5.6.3. See the figure on page 267.
Given: 

Find: 

(HINT:


To find:
Given:
Theorem used:
Angle bisector theorem:
If a ray bisects one angle of a triangle, then it divides the opposite side into segments whose lengths are proportional to the lengths of the two sides that form the bisected angle.
Calculation:
Given:
Then by anglebisector theorem, the ray
In a triangle the sum of the angles is
Multivariable Calculus
Finite Mathematics and Applied Calculus (MindTap Course List)
Calculus: An Applied Approach (MindTap Course List)
Mathematical Excursions (MindTap Course List)
Applied Calculus for the Managerial, Life, and Social Sciences: A Brief Approach
Mathematical Applications for the Management, Life, and Social Sciences
Statistics for The Behavioral Sciences (MindTap Course List)
Essentials of Statistics for The Behavioral Sciences (MindTap Course List)
Applied Calculus
Probability and Statistics for Engineering and the Sciences
Calculus (MindTap Course List)
Precalculus: Mathematics for Calculus (Standalone Book)
Intermediate Algebra
Elementary Technical Mathematics
Calculus (MindTap Course List)
Understanding Basic Statistics
Single Variable Calculus: Early Transcendentals, Volume I
Essentials Of Statistics
Calculus: Early Transcendental Functions
Single Variable Calculus
Calculus: Early Transcendentals
Finite Mathematics
Contemporary Mathematics for Business & Consumers
Trigonometry (MindTap Course List)
Elements Of Modern Algebra
Single Variable Calculus: Early Transcendentals
Calculus of a Single Variable
Elementary Geometry for College Students
Finite Mathematics for the Managerial, Life, and Social Sciences
Study Guide for Stewart's Multivariable Calculus, 8th
Study Guide for Stewart's Single Variable Calculus: Early Transcendentals, 8th
Calculus: Early Transcendental Functions (MindTap Course List)