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Sine or Cos Rule?. 15cm. 1. ?. 12cm. 30 o. a 2 = b 2 + c 2 – 2bcCos A. Cos A = b 2 + c 2 – a 2. 2bc. a b c . =. =. sinA sinB SinC. 15cm. 2. 30 o. ?. 14cm. a 2 = b 2 + c 2 – 2bcCos A. Cos A = b 2 + c 2 – a 2. 2bc. a b c . =. =.
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15cm 1. ? 12cm 30o a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
15cm 2. 30o ? 14cm a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
? 3. 50o 600 15cm a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
4. 12cm ? 14cm 15cm a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
15cm 5. 30o area? 14cm a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
15cm 1. ? 12cm 30o a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 need 3 sides! 2bc a b c = = sinA sinB SinC
15cm 2. 30o ? 14cm a2 = b2 + c2 – 2bcCos A need 2 sides and angle Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
? 3. 50o 600 15cm a2 = b2 + c2 – 2bcCos A need 2 sides and an angle Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC
4. 12cm ? 14cm 15cm a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc need 3 sides! a b c = = sinA sinB SinC
15cm 5. 30o area? area = ½ ab sinC 14cm a2 = b2 + c2 – 2bcCos A Cos A = b2 + c2 – a2 2bc a b c = = sinA sinB SinC