(geometry a) review of reasoning and proof quiz

1.) what is the inverse of the following statement? if it is raining, then i will carry an umbrella.

2.) write the following reversible statement as a biconditional: if two perpendicular lines intersect, they form four 90° angles.

3.) which reason justifies the statement m< dab that is 100°?

4.) use the vertical angles theorem to name a pair of congruent angles in the image shown.