Overcrowding and slums developed in many impoverished countries in the 20th century, mostly due to large migrations to cities from people looking for work.
Geography is literally 'the study of Earth' from 'ge (γη)' meaning earth and 'grapho (γραφω)' to write or to study.
The ninth planet is Pluto, but this was ruled a dwarf planet in 2006. It has a small surface area than Russia.
The lowland river system.
A glacial valley cross-sectional shape is a U shape whereas a stream valley is usually a V shape. The U shape comes from the scouring action of the alpine glaciers which carries rocks with it which can abrade the walls of the valley and the glacier occupies the whole valley so scours out such a shape whereas the stream cuts down and water washes in from the sides of the valley into the stream or river creating the V shape.
18
Explanation:
B is the vertex angle of isosceles triangle. So AB = BC and base side is AC.
As AB = BC
So,
5
x
−
28
=
2
x
+
11
5
x
−
2
x
=
28
+
11
3
x
=
39
x
=
39
3
=
13
AC =
x
+
5
= 13 + 5 = 18
