8. The length of the support is 7. 9 m
9. The length of the conveyer is 12m
3. a = 59m
A = 44°
B = 52°
4. c = 88. 6 mm
b = 49. 1 m
B = 34°
How to solve the trigonometry
8. We have the angle to be 20 degrees
Opposite side = x
hypotenuse = 23m
Using the sine ratio
sin θ = opposite/ hypotenuse
[tex]sin 20 = \frac{x}{23}[/tex]
Cross multiply
[tex]sin 20[/tex] × [tex]23 = x[/tex]
[tex]x = 0. 3420[/tex] × [tex]23[/tex]
x = 7. 9 m
The length of the support is 7. 9 m
9. The angle of elevation is 37. 3 degrees
Hypotenuse = 19 . 0m
Opposite = x
Using the sine ratio
sin θ = opposite/ hypotenuse
[tex]sin 37. 3 = \frac{x}{19}[/tex]
cross multiply
[tex]x = 0. 6059[/tex] × [tex]19[/tex]
x = 11.5
x = 12 m in 2 significant figures
The length of the conveyer is 12m
3. To determine the sides and angles, we use the sine rule;
[tex]\frac{a}{sin A} = \frac{b}{sin B} = \frac{c}{sin C}[/tex]
For side a, we use the Pythagorean theorem
[tex]c^2 = a^2 + b^2[/tex]
[tex]85^2 = a^2 + 67^2[/tex]
[tex]a = \sqrt{89^2-67^2}[/tex]
[tex]a = \sqrt{3432}[/tex]
a = 58. 58, a = 59m
To find angle A and B, use the sine rule
[tex]\frac{59}{sin A } = \frac{85}{sin 90}[/tex]
cross multiply
[tex]sin A[/tex] × [tex]85[/tex] = [tex]sin 90[/tex] × [tex]59[/tex]
make sin A subject of formula
[tex]sin A = \frac{59}{85}[/tex]
[tex]sin A = 0. 6941[/tex]
A = [tex]sin^-^1(0. 6941)[/tex]
A = 44°
[tex]\frac{67}{sin B} = \frac{85}{sin 90}[/tex]
cross multiply
[tex]sin B[/tex] × [tex]85[/tex] = [tex]sin 90[/tex] × [tex]67[/tex]
make sin b subject of formula
[tex]sin B = \frac{67}{85}[/tex]
[tex]sin B = 0. 7882[/tex]
B = [tex]sin^-^1( 0. 7882)[/tex]
B = 52°
4. To find the sides, we use the sine rule;
[tex]\frac{74. 0}{sin 56. 6} = \frac{c}{sin 90}[/tex]
Cross multiply
[tex]sin 56. 6[/tex] × [tex]c = sin 90[/tex] × [tex]74[/tex]
make 'c' subject of formula
[tex]c = \frac{74}{0. 8348}[/tex]
c = 88. 6 mm
To find length b, we use the Pythagorean theorem
[tex]c^2 = a^2 + b^2[/tex]
[tex]b^2 = c^2 - a^2[/tex]
[tex]b^2 = 88. 8^2 - 74^2[/tex]
[tex]b = \sqrt{7885. 44 - 5476}\\\\ b = \sqrt{2409. 44}[/tex]
b = 49. 1 m
[tex]\frac{74. 0}{sin 56. 6} = \frac{49. 1}{sin B}[/tex]
cross multiply
[tex]sin B = \frac{40. 99}{74. 0}[/tex]
B = [tex]sin^-^1(0. 5539)[/tex]
B = 34°
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