Two sides of a triangle measure 4 and 13 and the angle at the vertex where those two sides meet measures 100 degrees. What is the measure of thethird side?A O14.2В3.20.30DO12.9

Answered: wo sides of a triangle measure 4 and 13…

Holt Mcdougal Larson Pre-algebra: Student Edition 2012

1st Edition

ISBN:9780547587776

Author:HOLT MCDOUGAL

Publisher:HOLT MCDOUGAL

Chapter12: Angle Relationships And Transformations

Section12.3: Angles And Polygons

Problem 5C

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Related questions

Question

Two sides of a triangle measure 4 and 13 and the angle at the vertex where those two sides meet measures 100 degrees. What is the measure of the
third side?
A O
14.2
В
3.2
0.30
DO
12.9

Expert Solution

Step 1

$G i v e n t h a t T w o s i d e s o f t r i a n g l e m e a s u r e 4 a n d 13 a n d a n g l e a t v e r t e x w h e r e t h o s e t w o s i d e s m e e t m e a s u r e s 100 ° T o f i n d : t h i r d s i d e o f t r i a n g l e s o l u t i o n : u \sin g \cos i n e f o r m u l a I n a t r i a n g l e \cos B = \frac{a^{2} + c^{2} - b^{2}}{2 a c} w h e r e B = 100 ° a = 13, c = 4 \cos 100 ° = \frac{13^{2} + 4^{2} - b^{2}}{2 (13) (4)} 2 (13) (4) \cos 100 ° = 13^{2} + 4^{2} - b^{2} b^{2} = 13^{2} + 4^{2} - 2 (13) (4) \cos 100 ° b = \sqrt{13^{2} + 4^{2} - 2 (13) (4) \cos 100 °}$