Q. A ladder 10m long reaches a window 8m above the ground. Find the distance of the foot of the ladder from base of the wall.
reaches a window 8m above
ladder 10m
the ground.
10m
10m
??
distance of the foot of the
ladder from base of the wall.
A
B
C
(window)
(Ladder)
(Ground)
Soln.
In ΔABC,
∠ABC
=
900
[By Pythagoras theorem]
AC2
=
AB2
+
BC2
∴
( )2
=
BC2
+
( )2
∴
100
=
64
+
BC2
∴
BC2
=
100
-
64
∴
BC2
=
36
∴
BC
=
6m
∴
Distance of the foot of the ladder from the base of the wall is 6m.
10
8
8μ
AB
=
8m
,
AC
=
10m
,
AB represents the height at which ladder reaches the
window above the ground.
window above the ground. AC represents length of
the ladder.
Ex.6.5 (Q.9)
Sol.
AB represents the length of vertical pole.
AC represents the length of wire
BC is the distance of stake from the base of the pole.
A
B
Q. A guy wire is attached to a vertical pole of height 18m is
24m long & has a stake attached to the other end.
How far from the base of the pole should the stake be driven
so that the wire be will be taut?
C
18 m
24 m
?
18 m
24 m
B
A
C
In ΔABC,
∠ABC
=
90°
AC2
=
AB2
+
BC2
242
=
182
+
BC2
576
=
324
+
BC2
324
=
576
–
BC2
∴
∴
∴
[by Pythagoras theorem]
BC
=
6
∴
BC
=
∴
252
=
=
Ex.6.5 (Q.10)