The figure is a parallelogram. one diagonal measures 28 units.
is the figure a rectangle? explain.
a. no, it is not a rectangle because the diagonals are congruent.
b. no, it is not a rectangle because the sides of the parallelogram do not meet at right angles.
c. yes, it is a rectangle because the diagonals are congruent.
d. yes, it is a rectangle because the sides of the parallelogram do meet at right angles.

B. No, it is not a rectangle because the sides of the parallelogram do not meet at right angles.

Step-by-step explanation:

Law of cosines: a^2 = b^2 +c^2 - 2*b*c*cos(A)

Let's call

a = the side which is 28 units length

b = the side which is 21 units length

c = the side which is 20 units length  

A = the angle formed between sides b and c

Solving the formula for A, we get

a^2 = b^2 +c^2 - 2*b*c*cos(A)

2*b*c*cos(A)  = b^2 +c^2 - a^2

cos(A)  = (b^2 +c^2 - a^2)/(2*b*c)

A = arccos[(b^2 +c^2 - a^2)/(2*b*c)]

A = arccos[(21^2 +20^2 - 28^2)/(2*21*20)]

A = 86.1°

because linear equations are a lot simpler than quadratics equations, and linear equations formula is a lot easier to memorize. that's why i think they're harder.

1,589.63 in.^3

step-by-step explanation:

i hope this you : d