We know the perimeter is the total sum of all sides of the shape, we can use this to form an equation: the perimeter=1st side + 2nd side + 3rd side + 4th side 39a-7=9a+(5a+1)+(17a-6)+4th side.
Collect like terms to get 39a-7=31a-5+4th side
If we move everything but the 4th side over to the left we can solve
C. 8a-2=4th side is the correct answer

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3 years ago

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Help me please I have no clue

emmainna [20.7K]

Answer:

x = 12.8

Step-by-step explanation:

i use this calculator to find triangle measurements as long as you know like three values it works

https://www.calculator.net/triangle-calculator.html?vc=90&vx=&vy=10&va=38&vz=&vb=&angleunits=d&x=79&y=19

ik sending a link is hecka sus but you can just look up triangle calculator and it'll pop up