# Cosine + real numbers - problems

1. Trigonometric functions In right triangle is: ? Determine the value of s and c: ? ?
2. Regular 5-gon Calculate area of the regular pentagon with side 7 cm.
3. Forces In point O acts three orthogonal forces: F1 = 20 N, F2 = 7 N and F3 = 19 N. Determine the resultant of F and the angles between F and forces F1, F2 and F3.
4. IS triangle Calculate interior angles of the isosceles triangle with base 38 cm and legs 26 cm long.
5. Cuboid Determine the dimensions of cuboid a, b, c; if diagonal d=9 dm has angle with edge a α=55° and has angle with edge b β=58°
6. Triangle TBC TBC is isosceles triangle with base TB with base angle 63° and legs length |TC| = |BC| = 25. How long is the base TB?
7. Cotangent If the angle α is acute, and cotg α = 1/3. Determine the value of sin α, cos α, tg α.

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