# Mathswatch Clip 165 Loci Q7

Question 7 clip 165 says this: Three points, A, B and C are shown on the scale diagram below.On the diagram, construct and mark the 2 points that are:-the same distance from A and B -20m from C.I have bisected line AB and got all the middle points and then I drew a 2cm circle around C and there is only one point that is 20m from C and in the middle of AB. I got 3/4 marks and it's really annoying. Someone please help?
(edited 4 years ago)
I can get 2/4 marks, can you help me because I have got 3 days to do it
The way you have to do it is after you have created the bisector from AB you draw a line through the point of the bisector all the way to the other side of the circle and mark that point. Then put the compass the same way when you were creating the bisector and extend it to point 2. So now what you have to do is draw the bisector for point 2 to create potentially a isosceles triangle. Don’t get it I’ll put steps.(1. Draw a circle with a radius of 2cm around point C(2. Draw a line from point A to point B(3. Make the compass a bit longer than the center of line AB(4. Draw the two point bisector on AB(5.So now you have one point, draw a line all the way from the two point bisector to the other side of the circle.(6.mark point two(7. Put the compass on Point A or B then draw a bisector on the new marked point(8. Draw lines to the marked point from point A and B
(edited 3 years ago)
I still dont get it
I still dont get it
Could you show a video of you doing this for me please, I cant seem to still get 4/4 marks, i can only achieve 3.
Original post by raman23345
Could you show a video of you doing this for me please, I cant seem to still get 4/4 marks, i can only achieve 3.

Can you upload a photo of the question?
Original post by Muttley79
Can you upload a photo of the question?

Yeah sure, give me a couple minutes
Here u go @Muttley79
(edited 3 years ago)
Original post by raman23345
Here u go

There seems to be far too many lines - you should have the perpendicular bisector of AB then a circle of the correct radius - what are all the lines on the right?

You then need to mark the two points where the perpedicular bisector crosses the circle.
Original post by Muttley79
There seems to be far too many lines - you should have the perpendicular bisector of AB then a circle of the correct radius - what are all the lines on the right?

You then need to mark the two points where the perpedicular bisector crosses the circle.

I'm not really sure what im doing... my heads kinda scrambled since I been doing maths for the past 4 hours.. Is it possible if you could try attempting the question and then see what the difference is between our answers?
Original post by raman23345
I'm not really sure what im doing... my heads kinda scrambled since I been doing maths for the past 4 hours.. Is it possible if you could try attempting the question and then see what the difference is between our answers?

No - we can't post solutions - take a break and come back to it.
Original post by Shuriken_
The way you have to do it is after you have created the bisector from AB you draw a line through the point of the bisector all the way to the other side of the circle and mark that point. Then put the compass the same way when you were creating the bisector and extend it to point 2. So now what you have to do is draw the bisector for point 2 to create potentially a isosceles triangle. Don’t get it I’ll put steps.(1. Draw a circle with a radius of 2cm around point C(2. Draw a line from point A to point B(3. Make the compass a bit longer than the center of line AB(4. Draw the two point bisector on AB(5.So now you have one point, draw a line all the way from the two point bisector to the other side of the circle.(6.mark point two(7. Put the compass on Point A or B then draw a bisector on the new marked point(8. Draw lines to the marked point from point A and B

I know this is so late but thank you so much! You literally saved my life