Answer:
A rectangle is a parallelogram with at least one right angle is the best choice ⇒ answer A
Explanation:
* Lets revise the properties of the rectangle
# Each two opposite sides are parallel
# Each two opposite sides are equal in length
# Its two diagonals bisect each other and equal each other
# Its four angles are right angles
- The parallelogram can be a rectangle if:
# Two adjacent sides are perpendicular to each other means one
angle of its four angles is a right angle
- OR
# Its two diagonals are equal in length
* Lets solve the problem
- We will study the answers to chose the best one
# Answer A
- A rectangle is a parallelogram with at least one right angle
∵ Each tow opposite angles are equal in the rectangle
∵ One of the is right angle means its measure is 90°
∴ The measure of the opposite angle is also 90°
∵ The sum of the measures of the four angles is 360°
∴ The sum of the measures of the other two angles is;
360 - (90 + 90) = 180°
∵ They are equal to each other (opposite angles)
∴ The measure of each one = 180 ÷ 2 = 90°
∴ The measure of the four angles are 90°
∴ The four angles of the rectangle are right angles
* A rectangle is a parallelogram with at least one right angle is the
best choice