Guys plz ! is an emergency and idk what todo and if i get it wrong am failing

Dimitri used a coupon that saved him 80 percent, or $6.87. he paid $34.35 for the items.dimitri used a coupon that saved him 80 percent, or $27.48. he paid $34.35 for the items.dimitri used a coupon that saved him 80 percent, or $6.87. the price of the items before the discount was $34.35.dimitri used a coupon that saved him 80 percent, or $27.48. the price of the items before the discount was $34.35.

Acone with radius 5 cm and height 12 cm how many cm ?

Whats four fifths to the first power