Need help with 15 and show the work

Giving ad is congruent to bc and angle bcd is congruent to angle adc prove d e is going to ce

50 ! pls ! 12.  building codes regulate the steepness of stairs. homes must have steps that are at least 13 inches wide for each 8 inches that they rise.

a. discuss how to find the slope of the stairs.
b. describe how changing the width or height affects the steepness of the stairs.

The amount spent on food and drink by 20 customers is shown below what is the modal amount spent ?