Question

Two sides of a parallelogram measure 60 centimeters and 40 centimeters. If one angle of the parallelogram measures 1320, find the
length of each diagonal.
a.about 86.4 cm and 54.2 cm
c.about 91.7 cm and 54.2 cm
b. about 91.7 cm and 44.6 cm
d. about 86.4 cm and 44.6 cm​

Answer 1

Answer:

  b. about 91.7 cm and 44.6 cm

Step-by-step explanation:

The lengths of the diagonals can be found using the Law of Cosines.

Consider the triangle(s) formed by a diagonal. The two given sides will form the other two sides of the triangle, and the corner angles of the parallelogram will be the measure of the angle between those sides (opposite the diagonal).

For diagonal "d" and sides "a" and "b" and corner angle D, we have ...

  d² = a² +b² -2ab·cos(D)

The measure of angle D will either be the given 132°, or the supplement of that, 48°. We can use the fact that the cosines of an angle and its supplement are opposites. This means the diagonal measures will be ...

  d² = 60² +40² -2·60·40·cos(D) ≈ 5200 ±4800(0.66913)

  d² ≈ {1988.2, 8411.8}

  d ≈ {44.6, 91.7} . . . . centimeters

The diagonals are about 91.7 cm and 44.6 cm.