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.
Whether the isosceles triangle is acute, right or obtuse depends on the vertex angle. In Euclidean geometry, the base angles cannot be obtuse (greater than 90Â°) or right (equal to 90Â°) because their measures would sum to at least 180Â°, the total of all angles in any Euclidean triangle.