The vertices of a (convex) quadrilateral are usually designated with capital letters - https://domyhomework.club (e.g. A, B, C and D), the sides with small letters a, b, c and d, and the (interior) angles with α, β, γ and δ in the mathematical positive sense of circulation, unless the context requires other designations.
There are a and c as well as b and d opposite sides; a and b, b and c, c and d as well as d and a are adjacent sides - https://domyhomework.club/math-homework/ . The connecting lines of non-adjacent vertices (in the figure AC = e and BD = f) are the diagonals of the quadrilateral.
There are α and γ and β and δ opposite angles;
α and β , β and γ , γ and δ and δ and α are adjacent angles.
The perimeter u of a quadrilateral ABCD is the sum of the side lengths:
u = a + b + c + d
The sum of the interior angles of a quadrilateral ABCD is 360°:
α +β +γ +δ=360°.
The quadrilateral ABCD is divided by a diagonal into two triangles whose sum of angles is 180° each:
Δ ABC: α1+β+γ1=180°
Δ ACD: α2+γ2+δ=180°
With α1+α2=α and γ1+γ2=γ then in the quadrilateral ABCD holds:
α+β+γ+δ=360° (w. z. b. w. )
A parallelogram with a right angle is a rectangle - geometry homework help . Consequently, the following is true for the rectangle:
- The opposite sides are of equal length and parallel to each other.
- Adjacent sides are at right angles to each other.
- All four interior angles are equal. They are 90°.
- The diagonals are of equal length and bisect each other.