Angle of diagonals

Calculate the perimeter and the area of a rectangle if its diagonal is 14 cm and the diagonals form an angle of 130°.

Correct answer:

o =  37.2099 cm
S =  75.0724 cm2

Step-by-step explanation:

u=14 cm α=130   β=α/2=130/2=65   sinβ=a:u  a=u sinβ=u sin65° =14 sin65° =14 0.906308=12.68831 cm  cosβ=b:u  b=u cosβ=u cos65° =14 cos65° =14 0.422618=5.91666 cm  o=2 (a+b)=2 (12.6883+5.9167)=37.2099 cm
S=a b=12.6883 5.9167=75.0724 cm2

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Tips for related online calculators
The Pythagorean theorem is the base for the right triangle calculator.
See also our trigonometric triangle calculator.

We encourage you to watch this tutorial video on this math problem: video1   video2

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