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

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 14cm + 13cm + 5cm = 32cm

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

a = l x w
a = a x b
a = 8 x 1
a = 8

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° = 29, the value of d° is 151.

A trapezoid is a quadrilateral with one set of parallel sides.