Question

Find the value of x

Answer 1

http://curriculum.kcdistancelearning.com/courses/GEOMx-HS-CA10/a/assessments/T-TrianglesUnitExam/Geometry_Unit4_Exam_20q.gif

Answer 2

You can start by recalling that the interior angles of of a triangle equal 180, and if you look at the angle on the right hand side you will notice that it plus the missing angle also equal 180.
Set up your equation inside the triangle and solve for x or outside the triangle and solve for x.

Answer 3

uuhh

Answer 4

im confused

Answer 5

Inside you have:\[(4x+5)+(3x+20)+?=180\] On the right hand side you have:\[?+8x+15=180\] Solve for the ? and substituting in the other equation will allow you to solve for x.

Answer 6

how do i solve for the ?

Answer 7

Move everything to the other side like you would with any variable. If it is more appealing you can replace it with 'y'.

Answer 8

im so confused can you walk me step by step through the problem

Answer 9

I choose to start with the triangle because it offers the greatest condensing:
\[(4x+5)+(3x+20)+y=180 \rightarrow y=180-(4x+5)-(3x+20)\]
Any questions thus far?

Answer 10

no

Answer 11

Okay, so now you distribute the '-' \[y=180-4x-5-3x-20\] and combine like terms \[y=180-4x-5-3x-20 \rightarrow y=155-7x\] So if you now look at your triangle you have the lower left angle as 3x+20, the upper angle as 4x+5, and the lower right angle as 155-7x

Answer 12

Still okay?

Answer 13

yeah

Answer 14

Looking at the lower right of the drawing you see that the new equation you just found, plus 8x+15 equal 180 degrees. \[155-7x+8x+15=180\] Solve for x