Q. 125.0( 1 Vote )
A student wants to determine the height of a flagpole. He placed a small mirror on the ground so that he can see the reflection of the top of the flagpole. The distance of the mirror from him is 0.5 m and the distance of the flagpole from the mirror is 3 m. If his eyes are 1.5 m above the ground level, then find the height of the flagpole. (The foot of student, mirror and the foot of flagpole lie along a straight line).
Answer :
Here,
In the above Figure,
DE is the distance of student and mirror.
EG is the distance of mirror and flagpole.
CD is the height of student till its eyes.
FG is the height of flagpole which we need to find.
Now,
In ΔCDE and ΔFGE
∠FEG = ∠CED (by mirror property)
∠CDE = ∠FGE (both perpendicular given)
∴ ΔCDE ∼ ΔFGE
(∵ ΔCDE ∼ ΔFGE)
⇒ FG = 9 m
Rate this question :






















From the given figure, identify the wrong statement.
The points D and E are on the sides AB and AC of ΔABC respectively, such that DE || BC. If AB = 3 AD and the area of Δ ABC is 72 cm2, then find the area of the quadrilateral DBCE.
Tamil Nadu Board - MathFind the unknown values in each of the following figures. All lengths are given in centimeters. (All measures are not in scale)
A boy is designing a diamond shaped kite, as shown in the figure where AE = 16 cm, EC = 81 cm. He wants to use a straight cross bar BD. How long should it be?
The perimeters of two similar triangles are 24 cm and 18 cm respectively. If one side of the first triangle is 8 cm, then the corresponding side of the other triangle is
Tamil Nadu Board - MathFind the unknown values in each of the following figures. All lengths are given in centimeters. (All measures are not in scale)
In ΔABC, AB = AC and BC = 6 cm. D is a point on the side AC such that AD = 5 cm and CD = 4 cm. Show that ΔBCD ~ ΔACB and hence find BD.
Tamil Nadu Board - Math