# pre calculus

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A parallelogram has a 70 degree angle and sides 6 cm and 10 cm long. How long are its diagonals?

• pre calculus -

I assume you have had trig. Draw the figure. if it has a 70 degree acute angle, the other angle is 110.

Use the law of cosines:

shortdiag^2=6^2+7^2-2*6*7Cos70
longdiag^2=6^2+7^2-2*6*7Cos110

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