Please help! Medal & Fanned

http://prntscr.com/3an732

When I was working it out this is how I did it
180-30=149
179/2=74.5

Which is the correct answer but I just started guessing how to do it? Is that the correct way (the way I did it)

Question

Please help! Medal & Fanned

http://prntscr.com/3an732

When I was working it out this is how I did it
180-30=149
179/2=74.5

Which is the correct answer but I just started guessing how to do it? Is that the correct way (the way I did it)

anonymous · Answer

@hartnn

hartnn · Answer

there is also another way,

since AC is tangent
 angle BAC = 90 
so, 
angle YAC = 90 - angle BOY

hartnn · Answer

and angle BOY , as we know is 31/2 :)

hartnn · Answer

leading you to same 74.5 , which is correct!

anonymous · Answer

But its half confusing because 31 divided by 2 isnt 74.5

hartnn · Answer

yes yes,
angle BOY = 31/2 = 15.5 
but the question asked for  angle YAC

and angle YAC = 90- angle BOY = 90 - 15.5 = 74.5

anonymous · Answer

Alright that made a tad bit more sense thanks!

hartnn · Answer

welcome ^_^