Geometry

perpendicular lines are lines that MEET at right angles (90 degrees). Skew lines are lines that dont meet at all. Even though the gradients of two skew lines can multiply to be -1 (a property of perpendicular lines) They will not really be perpendicular as they don't accually meet. This can occur when the lines are in different planes.

if i dont not like carrots then i do not like vegetables

All squares are quadrilaterals.

All quadrilaterals are not squares.

There is no square that is not a quadrilateral.

What isn't the inverse of this statement(?)

If you do not do your homework then it will not snow.
If I do not do my homework, then it will not snow.

A conditional statement.

The sum of the 4 internal angles of a quadrilateral must sum to 360° (go look up the proof of this elsewhere).

For the sake of argument, let's call the 4 internal angles of a quadrilateral A, B, C, and D.

If they were all obtuse, then (by definition):

180° > A > 90°

180° > B > 90°

180° > C > 90°

180° > D > 90°

If you add them all up, you find that for the sum of the angles A+B+C+D

720° > A + B + C + D > 360°

but, A+B+C+D = 360°,

Since the assumption produces a result that contradicts this, the assumption cannot be true.

Q.E.D.

It is True!

The real answer is Bc . Hate these @

Figure B apex

In geometry, deductive rules can be used to prove conjectures.