Which of the following is a geometric sequence? A) 3,-9,27, -81,...
B)19, 15, 21, 27,...
C)4, 9, 16, 25,...
D)30,15, 0, -15,...
Please help
ILL GIVE BRAINLEST TO WHOEVER IS RIGHT

Solve the right triangle abc with right angle c, if b=30 degrees, and c = 10 a.) a=5, b=5, a=60 degrees b.) a=5, b=8.6602, a=60 degrees c.) a=5.7735, b=11.5470, a=60 degrees d.) a=8.6602, b=5, a=60 degrees