An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite:

d° = b° + c°

To find angle c, remember that the sum of the interior angles of a triangle is 180°:

180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 49° - 29° = 102°

So, d° = 29° + 102° = 131°

A shortcut to get this answer is to remember that angles around a line add up to 180°:

a° + d° = 180°
d° = 180° - a°
d° = 180° - 49° = 131°

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(5²) + 2π(5 x 6)
sa = 2π(25) + 2π(30)
sa = (2 x 25)π + (2 x 30)π
sa = 50π + 60π
sa = 110π

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(4 + 9)(5)
a = ½(13)(5)
a = ½(65) = \( \frac{65}{2} \)
a = 32\(\frac{1}{2}\)

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 6 x 2 = \( \frac{12}{2} \) = 6

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 1 + 4 + 3 + 9
p = 17