# Math Help - Finding the value of x?

1. ## Finding the value of x?

Okay I have already done this but I can't remember how to.

Also can you explain how you found it so I can remember again for future refrence.

Thanks for whoever helps

2. Originally Posted by JosephLive93
Okay I have already done this but I can't remember how to.

Also can you explain how you found it so I can remember again for future refrence.

Thanks for whoever helps
These are similar triangles, so the angles should be identical. Therefore, just equate both expressions to each other and solve for x.

3. Originally Posted by JosephLive93
Okay I have already done this but I can't remember how to.

Also can you explain how you found it so I can remember again for future refrence.

Thanks for whoever helps
I would isolate X to get the degree of the triangle, from there I would use formulas.

For example: your $(3x-10)^o$ would be x = 10 over 3.

4. I put in x+40=3x-10 and I ended up with x = 20 and I know the angle isn't 20 degrees by the looks.

5. Geometry Rule 1: Never assume things from the picture!

6. x+40=3x-10,

40 + 10 = 3x - x

. . . . .