Any idea how to answer this question? (Vectors)

"The corners of triangle PQR lie on a circle.
PQ = 3i + 4j
PR = -8i+6j
By showing that the triangle is right-angled, or otherwise, find the area of the circle."
It's from an Edexcel practise paper but I can't find the solutions anywhere... if you know how to do it (or know how to get the mark scheme) please tell!

Reply 1

mqb2766

21

Original post by moheat13

"The corners of triangle PQR lie on a circle.
PQ = 3i + 4j
PR = -8i+6j
By showing that the triangle is right-angled, or otherwise, find the area of the circle."
It's from an Edexcel practise paper but I can't find the solutions anywhere... if you know how to do it (or know how to get the mark scheme) please tell!

Have you sketched it, found any angles or lengths or ,...

(edited 2 years ago)

Reply 2

moheat13

OP

8

Original post by mqb2766

Have you sketched it, found any angles or lengths or ,...

I don't even know where to start, all I know is that the magnitudes are 5 and 10... I don't know how to sketch it when I don't know where the centre of the circle is.

Reply 3

mqb2766

21

Original post by moheat13

I don't even know where to start, all I know is that the magnitudes are 5 and 10... I don't know how to sketch it when I don't know where the centre of the circle is.

Draw the three points and triangle and upload? You may be able to see some intuition about where the circle is which guides the solution. There are a couple of ways you could go, one hint is given in the question about showing/recognising the triangle is right angled.

(edited 2 years ago)

Reply 4

bexxr

7

Original post by moheat13

"The corners of triangle PQR lie on a circle.
PQ = 3i + 4j
PR = -8i+6j
By showing that the triangle is right-angled, or otherwise, find the area of the circle."
It's from an Edexcel practise paper but I can't find the solutions anywhere... if you know how to do it (or know how to get the mark scheme) please tell!