A contractor plans to install two slides for the children to play in a park. For the children below the age of 5 years, she prefers to have a slide whose top is at a height of $1.5\ m$, and is inclined at an angle of $30^o$ to the ground, whereas for elder children, she wants to have a steep slide at a height of $3\ m$, and inclined at an angle of $60^o$ to the ground. What should be the length of the slide in each case?
Given:
A contractor plans to install two slides for the children to play in a park. For the children below the age of 5 years, she prefers to have a slide whose top is at a height of $1.5\ m$, and is inclined at an angle of $30^o$ to the ground, whereas for elder children, she wants to have a steep slide at a height of $3\ m$, and inclined at an angle of $60^o$ to the ground.
To do:
We have to find the length of the slide in each case.
Solution:
Let $AB$ be the height of the slide above the ground and $AC$ be the length of the slide for children below the age of 5 years.
Let $PQ$ be the height of the slide above the ground and $PR$ be the length of the slide for children above the age of 5 years.
From the figures,
In $\triangle ABC$,
$\frac{\mathrm{AB}}{\mathrm{AC}}=\sin 30^{\circ}$
$\frac{1.5}{\mathrm{AC}}=\frac{1}{2}$
$\mathrm{AC}=3 \mathrm{~m}$
In $\triangle PQR$,
$\frac{\mathrm{PQ}}{\mathrm{PR}}=\sin 60^{\circ}$
$\frac{3}{\mathrm{PR}}=\frac{\sqrt{3}}{2}$
$\mathrm{PR}=\frac{3 \times 2}{\sqrt{3}}$
$=\frac{6}{\sqrt{3}} \times \frac{\sqrt{3}}{\sqrt{3}}$
$=\frac{6 \sqrt{3}}{3}$
$=2 \sqrt{3} \mathrm{~m}$
Related Articles
- A carpenter makes stools for electricians with a square top of side \( 0.5 \mathrm{~m} \) and at a height of \( 1.5 \mathrm{~m} \) above the ground. Also, each leg is inclined at an angle of \( 60^{\circ} \) to the ground. Find the length of each leg and also the lengths of two steps to be put at equal distances.
- Draw a circle of radius $4\ cm$. Draw two tangents to the circle inclined at an angle of $60^{o}$ to each other.
- Draw a pair of tangents to a circle of radius 3 cm, which are inclined to each other at the angle of $60^{o}$.
- A kite is flying at a height of 75 metres from the ground level, attached to a string inclined at \( 60^{\circ} \) to the horizontal. Find the length of the string to the nearest metre.
- A tree is broken at a height of $5\ m$ from the ground and its top touches the ground at a distance of $12\ m$ from the base of the tree. Find the original height of the tree.
- Draw a pair of tangents to a circle of radius 5 cm which are inclined to each other at an angle of $60^o$.
- A balloon is connected to a meteorological ground station by a cable of length \( 215 \mathrm{~m} \) inclined at \( 60^{\circ} \) to the horizontal. Determine the height of the balloon from the ground. Assume that there is no slack in the cable.
- The angle of elevation of an aeroplane from point A on the ground is $60^{o}$. After flight of 15 seconds, the angle of elevation changes to $30^{o}$. If the aeroplane is flying at a constant height of $1500\sqrt{3}\ m$, find the speed of the plane in km/hr.
- The length of shadow of a tower on the play-ground is square root three times the height of the tower. The angle of elevation of the sun is: $( A) \ 45^{o}$$( B) \ 30^{o}$$( C) \ 60^{o}$$( D) \ 90^{o}$
- A $1.2\ m$ tall girl spots a balloon moving with the wind in a horizontal line at a height of $88.2\ m$ from the ground. The angle of elevation of the balloon from the eyes of the girl at any instant is $60^o$. After sometime, the angle of elevation reduces to $30^o$ (see figure). Find the distance travelled by the balloon during the interval."
- A kite is flying at a height of $60\ m$ above the ground. The string attached to the kite is temporarily tied to a point on the ground. The inclination of the string with the ground is $60^o$. Find the length of the string, assuming that there is no slack in the string.
- From a point on the ground, the angles of elevation of the bottom and the top of a transmission tower fixed at the top of a $20\ m$ high building are $45^o$ and $60^o$ respectively. Find the height of the tower.
- The angle of elevation of the top of tower, from the point on the ground and at a distance of 30 m from its foot, is 30o. Find the height of tower.
- Draw a pair of tangents to a circle of radius 4.5 cm, which are inclined to each other at an angle of $45^o$.
- From the top of a 7 m high building, the angle of the elevation of the top of a tower is $60^{o}$ and the angle of the depression of the foot of the tower is $30^{o}$. Find the height of the tower.
Kickstart Your Career
Get certified by completing the course
Get Started