Gre Formula Flashcards
What is the percent change formula
Percent change= difference
—————— x 100
Original
DIVISIBILITY
How to determine if a number is divisible by 2?
A number is divisible by two if the unit digit is divisible by two
DIVISIBILITY
How to determine if a number is divisible by 3?
A number is divisible by three if the sum of the digits is divisible by 3
Ex 2,145 is divisible by 3 BC 2➕1➕4➕5= 12➗3
DIVISIBILITY
How to determine if a number is divisible by 4?
A number is divisible by four if the last two digits from a number ➗ by 4️⃣
Ex: 712 is ➗4️⃣ bc 12➗4️⃣
DIVISIBILITY
How to determine if a number is divisible by 5?
Any number is divisible by five if the unit is 0 or 5
DIVISIBILITY
How to determine if a number is divisible by 6?
A number is divisible by six if it’s divisible by both 2(it’s even)and 3
Ex: 4,290 is divisible by 6 bc it’s divisible by 2 and by 3 bc 4➕2➕9➕0= 15/3
DIVISIBILITY
How to determine if a number is divisible by 8?
A number is divisible by eight if the last three numbers form a number the visible by 8
Ex:11,640 is divisible by 8 bc 640 is divisible by 8
DIVISIBILITY
How to determine if a number is divisible by 9?
A number divisible by nine if the sum of the digit is divisible by 9
Ex: 1➕8➕8➕1 = 18/9
DIVISIBILITY
How to determine if a number is divisible by 10?
Her number is divisible by 10 if the unit is zero
Vertical Angle
Vertical angles that cross each other when 2 angle intersect. Vertical angles are always equal.
X
If X was at the top it will be equal to Y below it
If A was to the left it would be equal to B to the right of it.
Parallel Line
Parallel lines never intersect. When a pair of angles is intercepted by a third, the two types of angles are formed big and small angle. Big angles are equals to big angles and small angles is equal to small angles.
The sum of any big angle and any small angle will always equal 180
Small / Big
——————/———————
Big / small
—————/————————
/
The rules of 180°
Every triangle contains angle that adds up to 180
What is an equilateral triangle🔼
An equilateral triangle is an angle in which all three sides are equal in length
Each angle = 60°
60*3= 180
60°
60°. 60°
What is an isosceles triangle?
🔻
A triangle in which two of the three sides are equal in length which means that two of the angles are also equal
40°
70°. 70°
Angle /side relationship and triangles
The longest side is opposite the largest internal angle( hypotenuse)
The shortest side is opposite the smallest internal angle
Equal sides are opposite.
What is the perimeter of a triangle?
The perimeter of a triangle measure the distance around it.
All you have to do to find the perimeter of a triangle is add up the length of the sides
What is that three side rules of a triangle?
The length of any one side of a triangle must be less than the sum of the other two size and greater than the difference between the other two sides.
5.
X. 3
5+3=8
5-2=2
Therefore the third side must be between 2 and 8.
Area of a triangle
A= 1/2 bh
The height of a triangle is defined as the length of a perpendicular line drawn from the point of the triangle to the base
/\
/ l \
/ I \
/ l \
/ h l \
/ l \
———b
What is the Pythagorean theorem
The theorem states that in a right triangle, the square of the length of the hypotenuse (the longest side) is equal to the sum of the square of the link of the two other side
a2➕b2= c2
a and b(other 2 sides)
C(length of the hypotenuse)
What are the most common right triangles
3: 4:5
1. 3
5
4
- Double the ratio
6
10
8
- Triple the ratio
9
12
15
What is the probability formula
Probability = desired outcome
—————————-
Total outcome
Ex: A bag contain 4 red balls, 3 orange balls, and 2 green balls. If three balls are chosen at random without replacement, what is the probability that all three balls are orange?
3 2 1. 1
— * — * — = ——
9 8 7. 84
RATIOS
l X. l. Y l Z l Total l ————- l——-l——l-—l———l Ratio l l l l l ————-l——-l——l—-l———l X l l l l l ———— l——-l——l—-l———l actual #
Average formula
Total
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# of. ✖️ Average
things l
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Rate/Distance/Time
Formula
Distance or Amount
➗——————————➗
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Time ✖️ Rate
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