A ladder 5m long, leaning against a vertical wall makes an angle of 65˚ with the ground.. a How high on the wall does the ladder reach?[r]
Trang 11 A ladder 5m long, leaning against a vertical wall makes
an angle of 65˚ with the ground
a) How high on the wall does the ladder reach?
b) How far is the foot of the ladder from the wall?
c) What angle does the ladder make with the wall?
2 Two towers face each other separated by a
distance d = 30 m As seen from the top of the
first tower, the angle of depression of the second
tower's base is 60o and that of the top is 30o
What is the height (in meters) of the second
tower? (Hint: 34.64m)
3 Two men on opposite sides of a
TV tower of height 20 m notice the angle of elevation of the top of this tower to be
45o and 60o respectively Find the distance (in meters) between the two men
(Hint: 31.55m)
4 Two men on the same side of a tall building notice the angle of elevation to the top of the building to be 30o and
60orespectively If the height of the building
is known to be h =110 m, find the distance
(in meters) between the two men
(Hint: 127.02m)
5 A pole of height h = 50 ft has a shadow of
length l = 50.00 ft at a particular instant of
time Find the angle of elevation (in
degrees) of the sun at this point of time
(Hint: 45O)
10 bài tập ứng dụng tỉ số lượng giác trong thực tế (lớp 9) – Đoan Hiền
Trang 26 You are stationed at a radar base and
you observe an unidentified plane at an
altitude h = 1000 m flying towards your
radar base at an angle of elevation =
30o After exactly one minute, your radar
sweep reveals that the plane is now at
an angle of elevation = 60o maintaining
the same altitude What is the speed (in
m/s) of the plane? (Hint: 19.25 m/s)
7 A ship of height h = 21 m is sighted from
a lighthouse From the top of the
lighthouse, the angle of depression to the
top of the mast and the base of the ship
equal 30o and 45o respectively How far is
the ship from the lighthouse (in
meters)? (Hint: 49.69m)
8 A flat 12 foot plank rests with one end on the ground and the other end
upon a 4 foot ledge
(a) How far from the base of the ledge is
the far end of the plank? (11.3 ft)
(b) What is the angle of elevation?
(19.46o)
9 Some wire connects from a pole to point on the ground at an angle of
depression of 80º On the ground, the wire
is 4.5 ft from the pole
(a) How much wire is used? (29.5ft)
(b) How high up the pole is the wire
connected? (25.52 ft)
10 At a certain distance, the angle of elevation to
the top of a building is 60º From 40 feet further back, the angle of elevation is 45º Find the height
of the building (Hint: 94.64 ft)