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165 pagesrevision 46935
printed 111 · PDF 112
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Q7c(i) - The formula for the area of a triangle is
1
2 × 𝑎× 𝑏× 𝑠𝑖𝑛𝜃 where 𝜃 is
the angle between the sides 𝑎 and 𝑏. Side lengths and area is known so angle
can be found.
Q7c(ii) - Cosine rule can be used here. 𝑎2 = 𝑏2 + 𝑐2 −2𝑏𝑐 𝑐𝑜𝑠𝜃 where
𝑎, 𝑏 and 𝑐 are side lengths and 𝜃 is the angle opposite to side 𝑎.
Q7c(iii) - AD = 12.3 + BD. This gives AD in terms of BD. Cos can now be
applied to get BD.