Geometry Review Triangles and Circles

Which angle is always less than 90 degrees

• obtuse

• right

• isosceles

• acute

Answer explanation

The angle that is always less than 90 degrees is called acute. Acute angles measure less than 90 degrees, making it the correct choice.

An obtuse angle

• an angle greater than 90 degrees and less than 180 degrees

• an angle less than 90 degrees

• an angle greater than 180 degrees

• an angle that is 360 degrees

Answer explanation

An obtuse angle is an angle greater than 90 degrees and less than 180 degrees, making the correct choice 'an angle greater than 90 degrees and less than 180 degrees'.

Which triangle only has 2 equal sides

• isosceles

• scalene

• equilateral

• none of the above

Answer explanation

The correct choice is isosceles because it is the only type of triangle that has 2 equal sides.

A scalene triangle has how many equal sides

• 3

• 1

• 2

• 0

Answer explanation

A scalene triangle has 0 equal sides, by definition. Each side of a scalene triangle has a different length, making them all unequal.

Select all of the statements that are true

• all angles in a triangle add up to 360 degrees

• All the angles in a triangle add up to 180 degrees

• A right triangle always has a 90 degree angle

• A ray starts at one point and goes on infinitely on the other

Answer explanation

The true statements are: All the angles in a triangle add up to 180 degrees, a right triangle always has a 90 degree angle, and a ray starts at one point and goes on infinitely on the other.

Select all that are true about parallel lines

• they have the same slope(m)

• they have different y-intercepts(b)

• The lines cross paths

• m=y2-y1/x2-x1

Answer explanation

Parallel lines have the same slope, different y-intercepts, and the formula to find slope is m=y2-y1/x2-x1.

Select all that are true about perpendicular lines

• Perpendicular lines never touch

• The angle of intersection is always a right angle

• Perpendicular lines have slopes that are opposite reciprocals

• Perpendicular lines cross paths

Answer explanation

Perpendicular lines always intersect at a right angle, have slopes that are opposite reciprocals, and cross paths.

To find slope you can use the rise over run method (rise/run)

• True

• False

Answer explanation

To find slope, you can use the rise over run method, which is represented as rise/run. Therefore, the statement is true.

Select all that are true about the lines of a slope

• a line coming from the top left of the graph going to the bottom right is a negative slope

• a line coming from the top right of a graph going to the bottom left forms a positive slope

• a horizontal line (-----)

  (straight across) / forms a neutral slope.

• A vertical line (going straight up and down) forms a undefined slope.

Answer explanation

The true statements about slopes are: negative slope from top left to bottom right, positive slope from top right to bottom left, horizontal line is neutral slope, and vertical line is undefined slope.

A reflex angle is

• an angle greater than 90 degrees and less than 180 degrees

• an angle greater than 180 degrees and less than 360 degrees

• an angle less than 90 degrees

• and angle that is 360 degrees

Answer explanation

A reflex angle is an angle greater than 180 degrees and less than 360 degrees, which is the correct choice among the options provided.