c = 7,8 cm
γ= 51°
β= 90°
Berechnung: cos (γ) = a/b (Bruch) ⌉ •c
cos (51°) • 7,8 cm = a
a ≈ 5.79
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c2 = a2 + b2 ⌉ -a2
c2 - a2 = b2 ⌉ √
√7,82 -5,792 = b
5,23 (cm) ≈ b
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180°- 90°-51° = α
39° = α