The slope of a line is 1. What is the slope of a perpendicular line?

Having a hard time understanding this question (see attachment).

Thanh and her crew are building a stage in the shape of a trapezoid for an upcoming festival. the lengths of the parallel sides of the trapezoid are 14 ft and 24 ft. the height of the trapezoid is 12 ft. what is the area of the stage? enter your answer in the box. ft²

Sara has 2 2/3 cup taco meat. she needs 1/6 cup to make one taco. how many tacos can sara make with the taco meat she has?