Pre-Algebra (Geometry Unit) Review Guide Answer Key

(*) – advanced questions (not responsible for on test)

  1. A.) How many triangles make up a 56 sided polygon?54 ( # of sides of the polygon minus 2)

B.) What is the sum of the interior angles of this polygon?9720 # of triangles multiplied by the sum of the interior angles of a triangle (54 x 180)

  1. What is a regular polygon? A polygon with all sides equal in length and all angles equal in measure
  1. Find the unknown angle measures of angles 1, 3 and 4.

Angle 1 (146): the angle that measures 34 degrees and angle 1 are adjacent angles

Angle 3 (34): the angle that measures 34 degrees and angle 3 are complementary angles

Angle 4 (34): 3 and 4 are vertical angles

  1. How many faces does an octagonal prism have?10 ( # of sides of the polygon (8) that makes up the prism plus 2)
  1. How many vertices does a decagonal prism have?20 ( # of sides of the polygon (10) that makes up the prism multiplied by 2)
  1. Find the unknown measures of angles 1 and 2.

Angle 1 (83): 180 (total sum of the interior angles of the triangle) minus 72+25 (given angles)

Angle 2 (97): Angles 1 and 2 are supplementary angles (sum is 180)

  1. Find the unknown measures of angles 1 and 2.

Angle 1 (115): 180 (total sum of the interior angles of the triangle) minus 28+37 (given angles)

Angle 2 (65): Angles 1 and 2 are supplementary angles (sum is 180)

  1. How many faces does a Pentagonal Prism have?7 (refer to #4 for explanation)

9. An octagon is a polygon with 8 sides.

A.)How many triangles make up an octagon?6 (# of sides of an octagon minus 2)

B.) What is the sum of the interior angles of an octagon? 1080 (refer to 1b for explanation)

C.) What is the angle measurement of each angle in a regular octagon? 135 (1080 divided by 8)

  1. A.)Find the unknown angle measures of angles 1, 3 and 4.

Angle 1 (67): the angle that measures 113 degrees and angle 1 are adjacent angles

Angle 3 (67): 1 and 3 are vertical angles

Angle 4 (113): the angle that measures 113 degrees and angle 3 are complementary angles

B.) Angles __113__ and __1__ are adjacent angles. Angles _1_ and _3_ are vertical angles.

  1. *Two angles are complementary if the sum of their measures is ___90____ degrees.
  1. *Two angles are supplementary if the sum of their measures is ___180____ degrees.
  1. Give the name of this polygon.Disregard this one (image didn’t copy)
  1. The distance across a circle through the center is the _____diameter______.
  1. *The distance between the center and any point on the circle is the ______radius______.
  1. *The distance around a circle is the ______circumference______.
  1. A trapezoid is a parallelogram. T/F (Explain)

False (in order to be a parallelogram it has to have two sets of parallel sides.

  1. A cube has how many edges?12 (# of sides that make up the polygon (4) x 3)
  1. A.) Plot the points for quadrilateral A (-7, 2) B (-6,5) C (-3,2) D (-2,5) What quadrant is this quadrilateral in?

Quadrant II (2)

B.) Using the points above, plot the new image of the dilated quadrilaterial if it has a scale factor of (0.5).

A’ (-3.5, 1), B’ (-3, 2.5), C’ (-1.5, 1), D’ (-1, 2.5)

  1. Which best describes the triangle according to its angles and sides.

c.) Scalene, acute

a.)Equilateral, acute

b.)Isosceles, acute

c.)Scalene, acute

d.)Isosceles, obtuse

  1. Draw a polygon that has exactly 4 lines of symmetry.

The polygon should be a square (lines of symmetry: vertical, horizontal, and two diagonal)

  1. What is the perimeter of a regular hexagon with a side length of 9 meters?

54 [# of sides (6) x length of each side (9)]

  1. Which best describes the figure?C.) parallel line segments

a.)Parallel lines

b.)Perpendicular line segments

c.)Parallel line segments

d.)Perpendicular lines

  1. A solid formed by polygons where the base can be any polygon and the other polygons are triangles is a ____pyramid______.
  1. What type of transformation is represented here?reflection
  1. *Find the value of x. 76
  1. *Find the value of x. 54
  1. Is this polygon convex or concave?concave
  1. A can of soup is an example of what type of a solid?cylinder
  1. *Find the missing side (c).26