A rectangle has 4 sides
each side is a right angle
a right angle by definition is 90 degrees

False
1. The surface area of a cone S is S=

, where r is the radius of the base and l is the slant height.
2. The slant height l is found as follows:



3.


4. The answer is C
Let A be the event
and B be the vent
. Since the intersection of the events
, the events A and B are mutually exclusive.
The number is either odd or even. Since
, the events are mutually exclusive and exhaustive.
Correct choice is "the number is either odd or even".
Hope it's 30. .....................