The length of segment EF is 12 cm. Triangle D E F is shown. Angle E D F is 90 degrees, angle D E F is 30 degrees, and angle E F D is 60 degrees. The length of hypotenuse E F is 12 centimeters. Which statements regarding triangle DEF are correct? Select three options.

The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?

The sat and act tests use very different grading scales. the sat math scores follow a normal distribution with mean 518 and standard deviation of 118. the act math scores follow a normal distribution with mean 20.7 and standard deviation of 5. suppose regan scores a 754 on the math portion of the sat. how much would her sister veronica need to score on the math portion of the act to meet or beat regan's score?

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.