Geometry

Question 1

right angle

Answer 1

equal to 90 degrees

Question 2

acute angle

Answer 2

less than 90 degrees

Question 3

obtuse angle

Answer 3

greater than 90 degrees

Question 4

straight line

Answer 4

equal to 180 degrees

Question 5

If two lines intersect

Answer 5

the sum of the resulting four angles equals 360

Question 6

polygon

Answer 6

Any figure with three or more sides. Total degrees = 180 x (n - 2) where n = # sides. For congruent polygons, Avg. degrees per side or degree measure = 180 x (n - 2)/n

Question 7

triangle (area)

Answer 7

A = (1/2)bh

Question 8

isosceles right triangle

Answer 8

(45-45-90) has sides in a ratio of x : x : x√2

Question 9

30-60-90 triangle

Answer 9

has sides in a ratio of x : x√3 : 2x, with the x side opposite the 30 degree angle

Question 10

equilateral triangle

Answer 10

three equal sides, each angle is equal to 60 degrees

Question 11

isosceles triangle

Answer 11

Has at least two congruent sides. Angles opposite congruent sides are congruent, converse true.

Question 12

right triangle

Answer 12

Has an interior right angle. Side opposite right angle is hypotenuse and always longest side, other two sides are legs.

Question 13

Pythagorean Theorem

Answer 13

a^2 + b^2 = c^2

Question 14

Pythagorean triples

Answer 14

Each side of certain right triangles are integers ( 3-4-5, 5-12-13, 8-15-17, 7-24-25). A multiple of a Pythagorean triple is a Pythagorean triple (e.g., 6-8-10).

Question 15

General Triangle Side Rules

Answer 15

Any given angle of a triangle corresponds to the length of the opposite side. The larger the degree measure of the angle, the larger the length of the opposite side. The length of the longest side can never be greater than the sum of the two other sides. The length of the shortest side can never be less than the positive difference of the other two sides.

Question 16

circle (area)

Answer 16

A = πr^2

Question 17

circle (circumference)

Answer 17

C = 2πr or C = dπ

Question 18

circle (arc length)

Answer 18

Arc Length = (measure of arc/360)(2πr), or L = (x/360)(C)

Question 19

circle (area of sector)

Answer 19

Area of Sector = (measure of arc/360)(πr^2), or S=(x/360)(A)

Question 20

circle general rules

Answer 20

A circle has 360 degrees. If two inscribed angles hold the same chord, the two inscribed angles are equal. An inscribed angle holding the diameter is a right angle.

Question 21

rectangle/square/parallelogram (area)

Answer 21

A = b x h or A = l x w (the base always forms a right angle with the height)

Question 22

trapezoid (area)

Answer 22

A = (base1 + base2)/2 x h, or A = 1/2(b1 + b2)(h)

Question 23

cube (surface area)

Answer 23

Surface Area = 6(s^2), where s = side

Question 24

cube (volume)

Answer 24

V = s^3

Question 25

rectangular solids (volume)

Answer 25

V = l x w x h

Question 26

rectangular solids (surface area)

Answer 26

Surface Area = 2(lw + lh + wh)

Question 27

right circular cylinder (volume)

Answer 27

V = π(r^2)h

Question 28

right circular cylinder (surface area)

Answer 28

Surface Area = 2πr^2 + 2πrh = 2πr(r + h)