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burhan101

A parallelogram has and area of 300 cm squared, the side lengths are 90 cm and 30 cm. What are the measures of the angle?

  • one year ago
  • one year ago

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  1. Xavier
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    |dw:1362374611174:dw| Can you express the area of the parallelogram in terms of these values. Also the measure of the angle based on trig identities

    • one year ago
  2. burhan101
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    I dont know what to do with it at all :S

    • one year ago
  3. burhan101
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    That was all the given information, how an i supposed to find any angles?

    • one year ago
  4. Xavier
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    Well what is the measure of the angle marked above in terms of the values and variables. Use a rig identity

    • one year ago
  5. burhan101
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    How tho, i dont understand

    • one year ago
  6. burhan101
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    theres not enough information given

    • one year ago
  7. Xavier
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    Can you express the area of the parallelogram in terms of the given values and the variable h we made up to represent the height?

    • one year ago
  8. burhan101
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    a= 90 x 30

    • one year ago
  9. Xavier
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    The area of a parallelogram is not side * size. It's base * height You can imagine splitting it into two triangles across the diagonal

    • one year ago
  10. burhan101
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    Yeah but there's no height given

    • one year ago
  11. Xavier
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    That's why we are using a variable that we'll solve for. Express the area in terms of the given information and the variable h

    • one year ago
  12. genius12
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    We know the length is 90 and width is 30. We need to find the measures of the angles. We also know that the area is 300. Area of parallelogram = L x h (H is height, not the side length of 30) We know Area is 300 and L = 90, but we don't know the height. So we can solve for h. 300 = 90h h = 300/90 = 10/3 Now that we know the height, we can figure out the angles. If you look at Xavier's diagram and the part that he labelled as "angle", that angle is also part of a triangle. That triangle has the height 10/3, same as the parallelogram, and a hypotenuse of 30, which is the other side length of the parallegram. 10/3 is the side opposite to the angle, and 30 is the hypotenuse. From SOH CAH TOA, we can use sine to figure out the angle. @burhan101 sin(x) = (10/3) / (30) = 10/90 = 1/9 We can use the inverse sine function to find angle x. x = sin^-1(1/9) = 6.38 Another thing we should is that one obtuse and one acute angle of a parallelogram are supplementary, meaning they add up to 180. If we know angle x,which is the acute angle is 6.38 degrees, we can subtract this from 180 to find the other angle, let's call it y : 6.38 + y = 180 --> y = 180 - 6.38 = 173.62 Therefore, the two angles x and y are x = 6.38 degrees, y = 173.62 degrees

    • one year ago
  13. burhan101
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    Area of a parallelogram is also magnitude of vector a and vector b

    • one year ago
  14. RadEn
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    u can use the law of sin : |dw:1362375710504:dw|

    • one year ago
  15. RadEn
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    solve for theta after u got the value of sin(theta)

    • one year ago
  16. RadEn
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    then for the other angle, just use the property of "consecutive interior angle" they sum 180 degrees, let the other angle is alpha : |dw:1362376183926:dw|

    • one year ago
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