Flashcards in Part 3: Geometry Deck (39)

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1

## What is the equation to calculate the number of degrees in a polygon?

### degrees = (n+2)*180, where n is the number of sides.

2

## What is the pythagorean theorem?

### a^2 + b^2 = c^2, used to determine length of sides in a triangle with one right angle (a right triangle).

3

## What is an equilateral triangle?

### a triangle where all three sides are the same length (congruent).

4

## What is an isosceles triangle?

### a triangle where two sides are congruent.

5

## What are the ratio of sides in an isosceles right triangle?

### a to a√2

6

## What are the ratio of sides in an 30-60-90 triangle?

### 2a to a√3 to a

7

## What is the area of a triangle?

### (bh)/2, which is base times height divided by 2.

8

## What makes for congruent triangles?

### All sides are the same. Or one side and two angels are the same. Or one angle and two sides are the same.

9

## What makes for similar triangles?

### All three angles are the same.

10

## What is the area of a quadrilateral?

### A = bh

11

## What is the area of a trapezoid?

### A = 1/2(b1 + b2)h

12

## In a circle, what is a chord?

### A line segment whose end points touch a circle's circumference.

13

## How to determine the length of an arc?

###
Given the angle of the arc, the length of the arc can be calculated with the following ratio:

arc angle/360 = arc length/circumference

14

## What is the area of a circle?

### πr^2

15

## What is the area of a sector?

###
Given the angle of the arc of the sector, the area can be calculated using the following ratio:

area of sector/area of circle = sector angle/360

16

## What is special about an inscribed triangle and it's angle (or side)?

### If one of the sides is the diameter of the circle, then it is a right triangle. If one of the angles of an inscribed triangle is 90 degrees, than one of its sides if the diameter.

17

## How is a polygon circumscribe a circle?

### If all sides of the polygon are tangential, then it circumscribes the circle.

18

## What are concentric circles?

### Circles that share the same center point.

19

## what is the volume of a rectangular solid?

### V = lwh

20

## What is the surface area of a rectangular solid?

### A = 2(lw + wh + hl)

21

## What is the a circular cylinder?

### Is a can but where the circles can be slid on their respective planes in any direction.

22

## What is a right circular cylinder.

### A can.

23

## What is an axis in a circular cylinder?

### It is the line connecting the center of both circles in a cylinder.

24

## What is the volume of a can?

### V = πr^2h

25

## What is the surface area of a can?

### A = 2πr^2 + 2πrh

26

## Given two parallel lines and two intersecting lines, one of the angles is 57 degrees and the other is 42. What are x and y.

### x is also 57 degrees. y is 180-42, which is 138 degrees.

27

## Given an isosceles triangle, and an outside angle of 125 degrees, what are x and y?

### y is 125 degrees. x is 180 - 55 - 55 = 70 degrees.

28

## Given two inside angles x and y and one outside angle z, what is their relationship to each other?

### x + y = z

29

## What is the sum of the interior angles inside a decagon?

### 8*180 = 1440 degrees

30