Ask your own question, for FREE!
Mathematics 9 Online
OpenStudy (anonymous):

Given that m

OpenStudy (anonymous):

OpenStudy (phi):

do you know which angle is <GHJ ?

OpenStudy (anonymous):

yes @phi

OpenStudy (phi):

Here is the picture

OpenStudy (phi):

any idea what the angle <GHJ + < IHJ add up to ? in the picture it's 154 + X (easier to type)

OpenStudy (anonymous):

That's where I get confused, because there is no actual number for x.

OpenStudy (phi):

it does not matter what the number is ... the idea is those two angles form a straight line and a straight line is an angle of how many degrees?

OpenStudy (anonymous):

Oh, I got x=26. I subtracted 154 from 180

OpenStudy (phi):

yes. we also know the two "marked angles" are equal (that is what the red arcs mean) if we call them Y (for convenience) the 3 angles of the triangle Y+Y+X= 180 and also from the first post 154+X= 180 so we can say 2Y+ X = 154+X or (subtract off X from both sides) 2Y= 154 now you can find Y (i.e. angle HIJ)

OpenStudy (anonymous):

I got y=77 degrees, thank you for all the help!!

OpenStudy (phi):

or we could use x=26 and say 2Y+26= 180 2Y= 180-26 2Y= 154 Y= 77

OpenStudy (phi):

the reasoning was a bit complicated... once people figured it out they said let the < GHJ be called an "exterior angle" and the exterior angle equals the sum of the two opposite angles. that lets you write down <GHJ = 2*<HIJ or 154 = 2 * <HIJ and <HIJ= 77

OpenStudy (anonymous):

I posted a similar one just now, it's even harder. Your explanation makes sense, thank you again!

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!