David wants to measure the diameter of his circular pool, but he does not have a tape measure long enough to reach across the pool. He measures around the pool edge, and
finds a circumference of 85 feet. Find the diameter. Show work.

i'm sorry mate, but i am not seeing any figures. i am unable to solve this for you.

its   c, f, a

step-by-step explanation:

large crystals result from very slow cooling.

evaporation of water: this would produce an evaporite which is a sedimentary rock. like a salt pan in a desert. not possible to have volcanic rocks originate this way.

crystalization in molten earth: slow cooling over time. (hundreds to millions of years)

crystalization at earth's surface: this results in fast cooling. (a few hours to a few months or years)

crystalization from cooling off hot water: that would be a hydrothermal deposit. while associated with volcanics they are not volcanic rocks themselves and usually occur fairly rapidly.