The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 2 x 9
a = 18

An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.

According to the Pythagorean theorem, the hypotenuse squared is equal to the sum of the two perpendicular sides squared:

c² = a² + b²
c² = 8² + 3²
c² = 64 + 9
c² = 73
c = \( \sqrt{73} \)

For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other
• same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°)

Applying these relationships starting with c° = 36, the value of d° is 144.

The formula for circumference is circle diameter x π:

c = πd
c = 14π