CY Lew's answer to Yong Quan's Secondary 3 E Maths Singapore question.

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CY Lew
Cy Lew's answer
89 answers (A Helpful Person)
1st
(a) i) QS** = 20** - 16**
QS = 12 cm
ii) sin angle SQR = 16 / 20 = 0.8
iii) sin angle PQS = sin (180-angle SQR) = 0.8

(b) Using sin rule,
sin SPQ / 12 = sin PQS / 18
sin SPQ = 0.8 x 12 / 18
Angle SPQ = Arc sin (0.8×12/18)
= 32.23 degrees