In the diagram below of parallelogram ABCD with diagonals AC and BD, m∠1=45° and m∠DCB=120°.Whatisthemeasureof∠2?

the answer is b.

surface area: 169π

volume: 366π

i got it down.

2.14x - 12.18 = -5.76

add 12.18 to each side

2.14x -12.18 +12.18 = -5.76 +12.18

2.14 x =6.42

divide by 2.14

2.14x/2.14 = 6.42/2.14

x=3

7 9/10 as an improper fractions is 79/10.

hope it : )

  b:   ∠x = 28.6°, ∠y = 31.2°, ∠z = 120.2°

step-by-step explanation:

this is one of those questions where "test taking skill" is all you need. the only answer that has angles that sum to 180° is the one shown above. the remaining choices do not describe the angles of a triangle.

if you want to do more work than simply adding the offered numbers, you can also check them against the law of sines. it should be true that

  x/sin(x) = y/sin(y) = z/sin(z)

and all of these ratios must be greater than 15, the longest side length.

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if you want to solve the triangle from scratch, i'd suggest solving for the largest angle using the law of cosines.

  z² = x² +y² -2xy·cos(z)

  z = arccos((x² +y² -z²)/(2xy)) = arccos(-75.11/149.4) = 120.182°

now you can find y from the law of sines

  y = arcsin(y/z·sin(z)) = 31.242°