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Flashcards in Math Deck (16)
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1

Total degrees of a polygon where n = # of sides

180(n-2)

2

Average degrees per side or degree measure of congruent polygon

180* ( (n-2)/n )

3

Area of triangle

1/2 * b * h

4

An isosceles right triangle (45-45-90) has sides in a ratio of

x * x * x sqrt(2)

5

A 30-60-90 triangle has sides in a ratio of

x * x sqrt(3) * 2x

6

Sets of numbers for each side of certain right triangles:

3-4-5

5-12-13

8-15-17

7-24-25

7

Basic triangle side rule

兩邊之和大於第三邊

8

Arc length

x/360 * 2πr

9

Area of sector

x/360 * πr^2

10

Formula of a line

y=mx+b

11

Formula of slope

m=(y1-y2)/(x1-x2)

12

The slope of two lines which are perpendicular to each other, if one slope is x, what is the slope of the other line?

-1/x

13

The distance formula

Sqrt( (x2-x1)^2 + (y2-y1)^2 )

14

Formula of sequence: 1+2+3+...+n is

n(n+1)/2

15

If 27/4 has reminder 3 and 6/4 has reminder 2 what's the reminder of (27+6)/4?

R1+R2 = 3+2 -4 =1

Because 3+2 is 5 which is larger than the divisor 4, hence we subtract the sum by divisor!

16

What is the reminder of 2/11

2

Every fraction that the numerator is greater than the denominator, the reminder is the numerator