What is the exact area of a circle with a diameter of 12 feet 36π square feet 81π square feet 324π square feet 1296π square feet

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

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?

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class