An engineer is asked to design a water sprinkler that will cover a field of 100 square yards that is in the shape of a sector of a circle of radius 15 yards. Through what angle should the sprinkler rotate?

50.96 degrees

Step-by-step explanation:

step 1

Find the area of complete circle with radius 15 yards

The area of the circle is given by the formula

substitute the given value of r

assume

step 2

Through what angle should the sprinkler rotate?

we know that

The area of the complete circle subtends a central angle of 360 degrees

so

using proportion

Find out the central angle of a sector of 100 square yards

570, the answer is 570, hope it

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.