Lewis structure. The Lewis structures, also called Lewis-dot diagrams or electron dot diagrams are pictures that show the bonding between a pair of electrons and the atoms of a molecule. Each dot represents one electron. Two dots side by side represent a lone pair of electrons.
Right angles are like corners and measure 90Â°. Acute angles are smaller than 90Â°. Obtuse angles are larger than 90Â°, but less than 180Â°. And straight angles are 180Â°, which is where the two lines go in the same direction and become like a single straight line. And that's all there is to it: each of the four types of angles in mathematics.
Lesson Summary. An acute angle is any angle smaller than 90 degrees. A right angle is an angle that measures 90 degrees. It doesn't matter how much smaller the angle is than 90 degrees; as long as it's smaller, it's acute. To unlock this lesson you must be a Study.com Member.