Most people missconsept that pentagrams are evil they are the sign of the devil, but this peace of information that is gave to you by a church or another type of religion authority is not true, the pentagram is symbol of power just like the cross. It is used in a lot of rituals to give them a extra boost. The pentagram isn't evil in itself, its the way it is used that makes it what it is.
The Pentagram is a symbol with 5 points all five of these points have a meaning and I will list the meanings down below;
The Tip of the pentagram is the first point it is the Soul.
Now go to the left to the left point that is the Air element.
Then the bottom left is the Water Element
The bottom right is the Earth Element
And the right side is the Fire element.
So you have the Soul, the Air, the Water, the Earth, and the Fire of the pentagram. All together they make a very powerful symbol.
The Pentagram also holds very special powers, if you wear this as a necklace it is said to keep away unwanted energies. The Pentagram is filled with many other special unique things but that was the basics of the Pentagram that you needed to know.
The pentagram formed from what the planet Venus looked like as it came into Earth's view. It was used in the Middle Ages to ward of witches, but only worked if it was drawn perfectly. It also represented the five wounds of Christ.
The pentacle is the star with the circle around it. As you said, the top triangle is Spirit/Akasha, followed be (going right) Air, Fire, Earth, and Water. The circle around the pentacle represents many things. Two common meanings is the circle of life, as well as the magick circle. The pentacle is used to ward away evil, cast circles, invocations, incantations, and many other things.
The church might view the pentacle (not really the pentagram) as evil because it is also used in Satanism. Some Satanist use the inverted pentacle in rituals. It represents Baphomet's ears, horns, and nose/beard. However, the inverted pentacle does not represent or mean evil.
Yeah am forced to got to a Christian school. One day I decided to wear a pentagram round my neck as a necklace. I got told to take it off. To which I kindly pointed out that the school rules say that you're aloud to wear a small item of religious significance as jewelry.