Answer:
45 m.
Step-by-step explanation:
Let the length of the shadow when the suns altitude = 60 degrees be x m.
Then tan 60 = h/x where h = height of the tower.
When the altitude is 45 we have:
tan 45 = h / (x + 45)
So
h = x tan 60 and
h = tan 45(x + 45) so
x tan 60 = tan 45(x + 45)
tan 45 = 1 so
x tan60 = x + 45
x tan60 - x = 45
x = 45 / (tan 60 - 1)
x = 25.98 m
So the height of the tower
h = 25.98 * tan 60
= 45 m.