The measure of an exterior angle of a triangle is equal to the sum of the measure of the two interior angles. Fill in the blank question.
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Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

Prove the following(cot0+cosec0)[tex](cot0 + cosec0) { }^{2} = \frac{1 + cos0}{1 - cos0} [/tex]