In the diagram AC is a diameter of circle ), If the slope of BC is -1/2. What is the slope of AB?

Question

anonymous · Answer

attachment

anonymous · Answer

@HelpBlahBlahBlah can u help?

helpblahblahblah · Answer

i dont know sorry

anonymous · Answer

ok thanks

anonymous · Answer

m=y2-y1/x2-y1 
anyone know is this the right formula?

anonymous · Answer

@amistre64 I think im doing this wrong

amistre64 · Answer

theres a nice property of circles,  any angle on the arc is half of the arclength it subtends ...|dw:1394721974594:dw|

amistre64 · Answer

since AC is the diameter, it cuts the circle in half ... therefore B has an angle of 180/2 = 90

since B is a right angle ... what property do slopes at right angles have?

anonymous · Answer

they  are perpendicular to each other

amistre64 · Answer

yeah .. and their slopes are neg_____  re____ricals  of _____  other ...

amistre64 · Answer

flip and negate ....

if m1 is perp to m2, then  m1 * m2 = -1 ... m2 = -1/m1

anonymous · Answer

lol negative reciprocals of each other

amistre64 · Answer

:)  so what is the slope of AB since BC has -1/2 ?

anonymous · Answer

1/2

amistre64 · Answer

thats a negate, but not a flip ... -1/2  negates and flips to 2/1

anonymous · Answer

oh ok so its 2

amistre64 · Answer

yep

amistre64 · Answer

if BC was 4/5  AB would have been -5/4  etc ....

anonymous · Answer

how to you make it so easy and i have been insane all morning. :) thank you!!!!

amistre64 · Answer

:)  good luck

amistre64 · Answer

knowing it was a right angle was the key is all ....

anonymous · Answer

thanks