PLEASE HELP
Find the measure of the arc or angle indicated.

Short arc LM = 110°

Comment

Any two angles that have their end points on the same end points as a chord and both moving away in the same direction (in this case  down ) are equal. This is a fundamental fact about circles.

Equation

2x + 55 =  x + 55

the only way this is going to make any sense is if x = 0. No other value is possible because it will destroy the equality.

Conclusion

Both angles = 55

But that's not what you are asked for.

What you are asked for

You want to know the measure of arc LM.  

The angle connecting the center of the circle with its two arms running through the end points of the chord = the measure of  arc LM

Draw a dot where the center of the circle is and call it O. Draw in <MOL  

<MOL = 2* either of the 55° = 2 (<LKM)  = 2 * 55 = 110° That's a property of the central angle.

The measure of arc LM = 110°

step-by-step explanation:

this can be solved first with pythagorean theorem, which tells us to square both legs of the triangle and sum it. this will be equal to the square of the hypotenuse.

the hypotenuse is the side "opposite" the 90 degree angle, which is x.

so we can write using pythagorean theorem,

simplifying:

to further simplify this radical, we need to use the property  

thus