+128408 Because it was " a cute" duck.......and acute ducks never cross at more than 90°.....!!!!
Hahahahahaha...............................................................................................................................................................................................................................................................I don't get it 
+2440 That’s true. If he wasn’t a cute duck then he would cross at more than 90° and no one would say why because that would be obtuse. 
+36915 ONE more (though not as good as the others)
If the duck 'crossed' at an angle greater than 180 degrees, it wouldn't need to use any 'reflex' to dodge cars!
