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Unformatted text preview: owing measurements
PQ = 650 metres
∠ QPR = 83º ∠ QPS = 127º
∠ PQR = 56º
∠ PRS = 65º
Calculate the area of the field. R P
S Given the sizes of A, a, and c if a < c sine A
a = c sine A
a>c no triangle is possible
the triangle is rightangled at C
only one triangle is possible
otherwise, two triangles are possible fitting the data given. (This is known as ‘the ambiguous case’.)
Investigate each of the following sets of data and say how many triangles are possible in each case. 14. A = 40º a = 6.1 cm c = 6 cm 20. A = 60º a = 5.08 cm c = 3.5 cm 15. A = 70º a = 5.25 cm c = 5.4 cm 21. A = 32.6º a = 5.16 cm c = 7.24 cm 16. A = 45º a = 15.4 cm c = 10.6 cm 22. A = 26.9º a = 13.0 cm c = 19.2 cm 17. A = 30º a = 4.5 cm c = 9 cm 23. A = 43.7º a = 21.3 cm c = 18.6 cm 18. A = 20º a = 6.79 cm c = 8 cm 24. A = 54.1º a = 39.5 cm c = 44.7 cm 19. A = 50º a = 3.09 cm c = 4 cm 25. A = 61.8º a = 42.6 cm c = 30.5 cm © Frank Tapson 2004 [trolPT:29] Trigonometry T/34
B The Cosine Rule: a 2 = b 2 + c 2 – 2 bc cos A
b2 + c2 –...
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This document was uploaded on 03/01/2014.
 Spring '14

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