Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 month ago

help please!?

given angle DBC = 20 degrees, AB=25 and DC=7, calculate the following measurements. 

angle A=

length of AD=

area of triangle ABC= 

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  • Ash
    Lv 7
    1 month ago
    Favourite answer

    tan ∠DBC = DC/BD

    tan 20° = 7/BD

    BD = 7/tan 20°

    BD ≈ 19

    sin ∠A = BD / AB

    ∠A = arcsin (19/25)

    ∠A = 49.5°

    AD = √(AB² - BD²) = √(25² - 19²) ≈ 16

    Area ΔABC = ½(AC * BD) = ½((AD + DC) * BD) = ½((16 + 7) * 19) = 218.5 

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  • 1 month ago

    given angle DBC = 20 degrees, AB = 25, and DC = 7, calculate the following measurements.  

    angle A = 53.13 degrees

    length of AD = 15

    area of triangle ABC = 220 units^2

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  • ?
    Lv 7
    1 month ago

    See below for work and solutions.

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  • sepia
    Lv 7
    1 month ago

     Given angle DBC = 20°, AB = 25, and DC = 7, 

     calculate the following measurements:

     

     Since ABD is a right triangle in which the hypotenuse measures 25

     the other sides of the triangle are 15 and 20 

     Because it is a right triangle one angle is obviously 90°. 

     The other two are approximately 36.87° and 53.13°.

     

     Angle A = 53.13°

     Length of AD = 15 

     Length of AC = 22

     Area of triangle ABC = 220 units^2

     Angle C = 70°

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  • Jim
    Lv 7
    1 month ago

    Since angles inside of a triangle add to 180, and a right angle is 90

    1) 180 -90 -20 = 70° for angle A

    2) Use SOHCAHTOA

    3) ½bh, but you must calc BD

    • julianna1 month agoReport

      You didn’t calculate angle A, you calculated angle C

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