When a river meets an ocean and spreads into what looks like a triangular shape, the landform or body of water being created is called a<u> Delta</u>.
Deltas are:
Formed at the point where a river meets another body of water
Formed such that they have a triangular shape
Caused by water erosion
Deltas take a triangular shape at the mouth of a river when the river is meeting a water body such as a lake or ocean.
They form because of water erosion resulting from when the river picks up soil particles and carries them to its mouth where they are deposited and obstruct the flow of water thereby creating a delta.
In conclusion, erosion causes a delta to form when water carries soil and deposits it at its mouth.
