Unit 1

Question 1

Polygons

Answer 1

a closed geometric figure with at least three straight sides. The point where two sides meet is called a vertex*. (The plural of vertex is vertices.)

Question 2

regular polygon

Answer 2

equal sides and equal angles. An irregular polygon* has sides that are not all the same length and interior angles that are not all the same measure. An irregular polygon is shown to the right:

Question 3

quadrilateral

Answer 3

a polygon with four sides and four vertices. Other polygons have different numbers of sides: a pentagon has five sides; a hexagon has six sides.

Question 4

parallelogram

Answer 4

any four-sided shape that has opposite, parallel sides that are equal in length, and, therefore, opposite angles that are equal in size.

A parallelogram with two sets of opposite parallel sides, two sets of opposite equal angles and diagonals shown.

Question 5

rhombus

Answer 5

has four equal sides, and the two opposite sides are parallel to one another. Opposite angles are equal to one another, all four adding up to 360°.

Question 6

trapezoid

Answer 6

have just one pair of opposite sides that are parallel, commonly referred to as base1 and base2. Unlike some other quadrilaterals, trapezoids can have four different-length sides and different angles.

Question 7

kites

Answer 7

have two sets of adjacent* sides that are of equal length. Kites have no parallel sides, and just one set of opposite angles is equal in size.

Question 8

equilateral triangle

Answer 8

have three equal angles (each measuring 60°)

Question 9

isosceles triangle

Answer 9

only 2 equal angles

Question 10

scalene triangle

Answer 10

have three angles of different sizes.

Question 11

circumference of a circle

Answer 11

2π𝑟 or π𝑑

Question 12

area of a circle

Answer 12

π𝑟²