### Dictionary Rank of a Word | Permutations & Combinations

PERMUTATIONS & COMBINATIONS Rank of the word or Dictionary order of the English words like COMPUTER, COLLEGE, SUCCESS, SOCCER, RAIN, FATHER, etc. Dictionary Rank of a Word Method of finding the Rank (Dictionary Order) of the word  “R A I N” Given word: R A I N Total letters = 4 Letters in alphabetical order: A, I, N, R No. of words formed starting with A = 3! = 6 No. of words formed starting with I = 3! = 6 No. of words formed starting with N = 3! = 6 After N there is R which is required R ----- Required A ---- Required I ---- Required N ---- Required RAIN ----- 1 word   RANK OF THE WORD “R A I N” A….. = 3! = 6 I……. = 3! = 6 N….. = 3! = 6 R…A…I…N = 1 word 6 6 6 1 TOTAL 19 Rank of “R A I N” is 19 Method of finding the Rank (Dictionary Order) of the word  “F A T H E R” Given word is :  "F A T H E R" In alphabetical order: A, E, F, H, R, T Words beginni

### Different Types of Angles

Different Types of Angles
Beautiful and useful blog on different types of angles, useful for the students of 5th onword . Complete knowledge about different types of angles in mathematics

Different Types of Angles
Zero Angle:- Angle of 0o is called zero angle.

Acute angle :- Angle greater than 0o but less than 90o is called acute angle.

Right Angle:- Angle of 90o is called right angle.

Obtuse Angle:- Angle greater than 90o but less than 180o is called obtuse angle.

Straight Angle :- Angle of 180o is called straight angle.
Different Types of Angles
Reflex angle :- Angle greater than 180o but less than 360o is called reflex angle.

Complete angle:- Angle of 360o is called complete angle.

Linear Pair of Angles:-
When sum of two adjacent angles is  180o, then pair of angles is called  a linear pair of angles .

Two angles with one common arm are called adjacent angles.

Complementary Angles :-
If sum of any two angles is 90o then angles are called complementary angles.
Different Types of Angles
Supplementary Angles:-
If sum of any two angles is 180o then angles are called supplementary angles.

Vertically Opposite Angles:-
When two lines intersect each other then vertically opposite angles are formed. Vertically opposite angles are always equal.
Different Types of Angles
Parallel Lines and Angles

When two or more parallel lines are intersected by a transversal then :-

Alternate angles are equal:- $\angle 3=\angle 5,\: \: \: \angle 4=\angle 6$
Corresponding angles are equal:-  $\angle 1=\angle 5,\: \: \: \angle 2=\angle 6,\: \: \: \angle 3=\angle 7,\:\: \: \angle 4=\angle 8$
Alternate Exterior Angles are Equal:-  $\angle 1=\angle 7,\: \: \: \angle 2=\angle 8$
Co - interior Angles are Supplementary :- $\angle 4+\angle 5=180^{o},\: \: \: \angle 3+\angle 6=180^{o}$
Vertically Opposite angles are equal:- $\angle 1=\angle 3,\: \: \angle 2=\angle 4,\: \: \angle 5=\angle 7,\: \: \angle 6=\angle 8$
Different Types of Angles
Sum of three angles of a triangle is 180o
Exterior angle of a triangle is equal to the sum of interior opposite  angles.

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