​ Can somebody please help me ASAP? I've been waiting since this morning.

First one:

1)  Since AP = PB = 4 and triangle(APB) is a right triangle:  AB²  =  AP² + BP² 

               --->   AB²  =  4² + 4²   -->  AB  =  .......

2)  Since BP = PD and P is the midpoint of BD   --->   BD = 8

     Since triangle(BDC) is similar to triangle(BPA), DC = 8.

3)  Since(triangle(BDC) is a right triangle:  BC²  =  CD² + BD² 

               --->   BC²  =  8² + 8²   --->   BC  =  .......

4)  Now, add up the parts.

Second one:   (use Pythagorean triples)

-- try a 13 -13 -20 isosceles triangle.

2)              first triangle              17--30--17

                 second triangle         17--16--17