Find the radius of a particle's circular path

[David Williams]

Homework Statement

A particle moves along a circular path over a horizontal xy plane at a constant speed. At time t1= 3.00s, its acceleration vector is given by (3i-5j) m/s^2. At time t2=7.00 s, its acceleration is given by (-3i+5j) m/s^2.
Find the radius of the particle's circular path.

Homework Equations

centripetal acceleration = v^2/r

The Attempt at a Solution

Stumbling around for about an hour with no clue what to do... left me with nothing to show for.

 

[BvU]

Hello David,

no clue what to do

Doesn't count as an attempt at solution; according to the PF rules we're not allowed to assist in such a case.

But for a first post I'll stick out my neck : You have two acceleration vectors; notice anything particular about them ? Could that help you towards another expression involving $v$ and $r$ ?