If ABCD is a rectangle, and m∠ADB=55°, what is the value of x?

x= 70

Step-by-step explanation:

Rectangles have four right angles (angles of 90 degrees).

The point of intersection of the diagonals divides each one of them into two equal parts.

Knowing this, we can conclude that:

m\angle c=m\angle b=55\°

Therefore, since the sum of the interior angles of a triangle is 180 degrees, we can find the value of "x":

x+m\angle c+m\angle b=180\°\\x=180\°-55\°-55\°\\x=70\°

a. she will receive a refund of $278.

step-by-step explanation: