KanjiJLPT N2
Angle

angle, corner, square, horn, antlers

Mnemonic

A bull's horn curves into a sharp hook at its tip. The beast knows how to utilize that horn — it tilts its head until it finds the perfect angle of attack, driving the point right where two surfaces meet.
Additional thoughts
Visualize the bull's curved horn: the hook shape at its tip, and the animal utilizing it by adjusting its head angle. The horn itself IS the angle — a sharp projection jutting outward.
Quick recall
A bull's hook-shaped horn, utilized at the perfect angle of attack.

Details

The keyword for 角 is angle. This kanji refers to a corner, horn, or angle — essentially any point where two lines or surfaces meet to form a sharp projection. It originally depicted an animal's horn, which naturally comes to a point at an angle. By extension, it can also refer to squareness, a street corner, or the concept of angularity in general.
On'yomi
かく
Kun'yomi
かど、つの

Used in kanji