Question 199732
they would both be diameters IF they intersect at their midpoints. But it easy to see that two chords could be the same length AND perpendicular but NOT a diameter IF they intersect somewhere other than their midpoints.

Make an circle.
Draw a chord that is 'far away' from the center of the circle.
Now see that you could take a chord of the same length and 'slide it' towards one end of the first chord. 
Make it perpendicular and slide it down until the ends touch the circle.

Do those two chords meet the congruent and perpendicular requirements? Are they a diameter?