In triangle DEF, segment DJ is a perpendicular bisector of side EF. If EJ is 3y-8 and JF is 7y-40, what is the length of JF? Group of answer choices:

A. 12

B. 40

C. 16

D. 15

David is spreading mulch on a triangular area of his flower bed. the coordinates of the vertices of the area are (1, 3), (9, 3), and (4, 6). what is the area of the triangle if each square has an area of 3 square feet?

Acircle has a circumference of 28.36 units what is the diameter of the circle

Needmax recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.