Is quadrilateral RSTV a rectangle?
(1) The measure of ∠RST is 90o
(2) The measure of ∠TVR is 90o
It's clear E. Sure RSTV can be a rectangle but it also can be a kite:
The attachment Kite.png is no longer available
Can you provide some more explanation here.
1. Straight lines never bends...even at infinity.
2. In your kite example angle at S and V is 90, but then line started bending inwards, making it a kite.
3. Mathematically lines originating from angle S and V will travel straight and intersect other lines perpendicularly. i.e Only applicable when opposite ends are at 90.
Real life example, open MS Paint and see how we draw rectangles in it. You click at one end and drag cursor diagonally. one can see opposite ends at right angle.
Frankly I don't see the lines bending inwards in the figure. Anyway, are you implying that such figure is not possible? If yes, then you are wrong:
The angles marked as right must be right because if an inscribed triangle has diameter as its hypotenuse then the triangle must be right angled. So, we can inscribe a right triangle in a circle and then draw its mirror image around the hypotenuse to get a kite.