Help!

http://prntscr.com/dk2ajh

Question

Help!

http://prntscr.com/dk2ajh

erma_arii · Answer

@3mar

3mar · Answer

Well, I am here.
Did you try to start?

erma_arii · Answer

no im confused actually.

3mar · Answer

What is the measure of the inscribed angle that is drawn in a semicircle?

erma_arii · Answer

um dont know?

3mar · Answer

|dw:1481874157116:dw|

erma_arii · Answer

do i do (x+10)=(2x-25) to find x?

3mar · Answer

That is not quite right!
the measure of the inscribed angle that is drawn in a semicircle is always $\color{red}{90}$ degree
...
agree?

erma_arii · Answer

yeah

3mar · Answer

That is good!

Do you know that the sum of the measures all interior angles of a triangle is 180?

erma_arii · Answer

yes

3mar · Answer

How many degrees?

erma_arii · Answer

180

3mar · Answer

Very nice....

Can you now add all these angles (x+10) and (2x-25) and 90 up to 180 ...?
Write out this equation, please....

danjs · Answer

Those little dash marks through the sides means those are equal lengths. Isocelese triangle. THe angles opposite equal sides are also equal angles. So yeah just set the two angles equal.

3mar · Answer

Oh sorry I know that but I did see them...
@erma_Arii 
Yes you can set the two angles equal...
|dw:1481874977360:dw|
although $$x+10+2x-25+90=180$$ is also available to calculate the value of x...