Trouble with Trig Functions----Need HElp (1 Viewer)

[sando]

Can someone please give me a full working out---much appreciated

Q. 1. A chord 8mm long is formed by an angle of 45' subtended at the centre of a cirlce. Find:
a) the radius of the circle
b) the area of the minor segment cut off by the angle


i just cant seem to understand the whole concept of finding the minor segment

does anyone hav an easy way to explain it?

 

[Riviet]

The question (part b) is badly worded. Having said that, I don't get how you can have a minor segment of a minor segment. Just calculate the area of the minor segment for now.

 

[sando]

Edited question: added in sumthing by mistake

still don't know what to do ?????

 

[Riviet]

Ok, that's much much much more clearer, hehe. I'll explain it from scratch; draw a circle, draw the centre and label it O. Draw two radii which make an angle of about 45 degrees, and label that angle with 45 degrees. From the two points where the radii touch the circumference, draw an interval connecting the two points to form an isosceles triangle, and label that length 8mm. Now in that sector, which consists of the triangle and that other bit of area, the bit of area IS the minor segment.
Use the angle sum of a triangle to work out the other two angles in the isosceles triangle, and then you can use the sine rule to find the radius.

Edit: sando has worked it out.

 

[boongsta]

Smart man riviet well done

 

[darlking]

Hey dudes.
Can you redo this question with working out???
Q. 1. A chord 8mm long is formed by an angle of 45' subtended at the centre of a cirlce. Find:
a) the radius of the circle

I'm scribbling all over man. :l

 

[darlking]

Don't worry, i figured... Its
r= 8sin67.5' / sin45'
r= 10.5