Find the base circumference of a cone with height 10 cm and volume 90π cm3 .

The base circumference of the cone is .

Can some one me with this math problem?

What is 32+4 x (16 x 1/2) -2 show your work}

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?