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GRADE: 8 TRIGONOMETRY CHAPTER: 18

1. In the figure AB is parallel to DC, ∠ ADC=36 °, ∠ AEC=90 °, AB=8 cm ,DE=4 cm and EC=10cm. Calculate, to 2 decimal places, (a) the length, in cm, of AE.(b) the area, in cm2, of the trapezium ABCD.

2. In the figure given below ∠DAB=∠DBC=90 ° , ∠ ADB=40 °, ∠BCD=64 ° and BC=12cm.Find, giving your answers to 3 significant figures,(a) the length, in cm, of DB.(b) the length, in cm, of AB.(c) the area, in cm2, of ∆DBC .

3. In ∆ ABC ,BC=12cm, AD=14 cm ,∠CBD=33 ° and ∠ ADB=90° .Calculate, to 3 significant figures,(a) the length, in cm, of DC.(b) the length, in cm, of BD.(c) the size of ∠BAD.

SAF. DEPARTMENT OF MATHEMATICS. 1

ISLAMIA ENGLISH SCHOOL, ABU DHABI.

4. In the triangle ABC , AC=12.6 cm, AB=4.9cm ,∠BAD=35 ° and ∠BDC=90 °. Calculate

(a) the length, in cm to 2 significant figures, of BD.(b) the length, in cm to 2 significant figures, of AD.(c) to the nearest degree, the size of ∠BCD.

5. The top T of Mount Everest is 8840 m above sea level. From the peak P, 5000 m due east of Mount Everest, the top of Everest is observed at an angle of elevation of 24°.Find, in m to the nearest 100 m, the height of the peak P above the sea level.

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SAF. DEPARTMENT OF MATHEMATICS. 2

ISLAMIA ENGLISH SCHOOL, ABU DHABI.