First, the area of the triangle = base × height ÷2. The formula S= a×h÷2.
Second, the square area = side length × side length formula S = a× a.
3. area of rectangle = length× width formula s = a× b.
Fourth, the area of parallelogram = base × height formula S = a× h.
5. trapezoidal area = (upper bottom+lower bottom) × height ÷2 Formula S=(a+b)h÷2.
Sixth, the sum of internal angles: the sum of internal angles of a triangle = 180 degrees.
Seven. Cuboid volume = length× width× height formula: V=abh.
8. cuboid (or cube) volume = bottom area × height formula: v.