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A tree breaks and falls to the ground such that its upper part is still partially attached to its stem. At what height did it break, if the original height of the tree was 24┬аm and it makes an angle of 30┬░ with the ground?
9 m
10 m
12 m
8 m
8 m
For a tree breaking at height h and making angle 30┬░ with the ground, the ratio of height to total height is h:H=1:(1+2)=1:3. Thus, h=324тАЛ=8┬аm.
Original height of the tree H=24┬аm, Angle made with the ground ╬╕=30┬░
h=1+csc╬╕HтАЛ
For a tree breaking at height h and making angle 30┬░ with the ground, the ratio of height to total height is h:H=1:(1+2)=1:3. Thus, h=324тАЛ=8┬аm.
Students often confuse the broken part (hypotenuse) with the remaining height or mistakenly use sin30┬░ directly without accounting for the total height being the sum of the remaining height and the fallen part.
Define Variables and Setup Triangle
Let the total height of the tree be H=24┬аm. Let the tree break at height h from the ground. The remaining part is of height h, and the fallen upper part forms the hypotenuse of a right-angled triangle with length L=HтИТh.
H=h+L=24
Apply Trigonometric Ratio (Sine)
In the right-angled triangle formed with the ground, the angle ╬╕=30┬░. The perpendicular is h and the hypotenuse is L. Using sin30┬░=hypotenuseperpendicularтАЛ:
sin30┬░=LhтАЛ=21тАЛтЯ╣L=2h
Substitute and Solve for Height h
Substitute L=2h into the total height equation H=h+L:
24=h+2hтЯ╣3h=24тЯ╣h=324тАЛ=8┬аm
D is correct because calculating the break height using trigonometry yields 8┬аm.
Similar problems frequently appear in height and distance applications of trigonometry involving shadows, ladders, and broken poles.