Lines and Types in Mathematics

len Alfred Ajibola - Fri, 12th July, 2019 @ 12:20

Topics in Mathematics

Angles: Type of angles based on degree measurement Angle Pairs: Types of angle pairs Conversion of Number Bases explained with examples Angles: What are Angles? Categories of Angles Lines and Types in Mathematics Number Base System - Table showing the Number Bases with explanations Mathematics Scheme of Work, SS1, 3rd Term Mathematics Scheme of Work, SS1, 2nd Term Mathematics Scheme of Work, SS1, 1st Term Trigonometry - Sine, Cosine and Tangent explained with worked examples Quadratic Equation - Factorization of Quadratic Equation Algebra - Explanation and Worked Examples on Algebra

Academic Questions in Mathematics

Please check out our Test Your Knowledge page to see all Questions and Answers

Factorize 12a2 - 20a + 3

  • A. (6a - 1)(2a - 3)

  • B. (6a - 1)(2a + 3)

  • C. (6a + 1)(2a - 3)

  • D. (6a + 1)(2a + 3)

  • E. (-6a + 1)(2a - 3)

  • F. (-6a + 1)(2a + 3)

Simplify 10ab + 7ab

  • A. 17ab2

  • B. 17a2b2

  • C. 3ab2

  • D. 3a2b2

  • E. 17ab

  • F 3ab

Which of the following is not a type of angle?

  • A. Right angle

  • B. Left Angle

  • C. Acute Angle

  • D. Complete Angle

  • E. Straight Angle

  • F. Reflex angle

Two lines that can never meet each other are best considered as _____ lines.

  • A. straight
  • B. vertical
  • C. horizontal
  • D. parallel
  • E. oblique
  • F. perpendicular

An angle at exactly 90o is a/an _____ angle.

  • A. acute
  • B. obtuse
  • C. reflex
  • D. right
  • E. complete
  • F. straight

Slanted or tilted lines that will finally meet at some point but NOT at a right angle are referred to as _____.

  • A. Oblique
  • B. Curved
  • C. Vertical
  • D. Perpendicular
  • E. Parallel
  • F. Horizontal

The two sides that forms an angle are referred to as the _____.

  • A. Arms
  • B. Vertexes
  • C. Bays
  • D. Zones
  • E. Limbs
  • F. Dune

The point where the two sides of an angle meet is termed the _____.

  • A. Arms
  • B. Vertex
  • C. Bays
  • D. Zones
  • E. Limbs
  • F. Dune



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Lines in Mathematics:

Lines are quite important in mathematics because having a good understanding of them would help students to better understanding angles.

Please read on Angles and Types of Angles here.

Every form of line must begin from a point. In fact, a line can only be drawn within two different points.

Just think of a point as a location.

A point has no length, depth or width. It is generally represented as a dot.

Note: A point is not necessarily a dot. A dot shows you where the point (location) really is.

As an instance, Below are 5 different points represented by a dot.

. . . . .

A line can be defined as the path between two points.

A line usually have a length but may have no width.

Lines are generally put into 2 categories in mathematics. Every other type of line will lie within these 2.

The 2 categories of lines are Straight Lines and Curved Lines.

Please read on the Type of Lines in Technical Drawings here.

  • Straight Line

When the path between two points are straight, then the line that is associated with the path is a straight line.

A straight line can be drawn in any direction. It could go from north to south or east to west.

The image below shows a straight line running from east to west.

EAST ______________________ WEST


Types of Straight Line

Below are types of straight line:

1. Horizontal Line

A horizontal line is a line that runs from left to right or east to west in a straight line.


2. Vertical Line

A vertical line runs from top to bottom or north to south in a straight line.


3. Perpendicular Line

The word perpendicular simply means “at right angles”.

Two lines are said to be perpendicular if they meet or cross each other at a right angle.

Note: A right angle is an angle at ninety degrees (90o).

Perpendicular Line - Len Academy

In the diagram above, you will observe that the line CD meets line AB at point E, which is at a right angle (90o). Line CD is therefore said to be perpendicular to line AB at point E.

Note the followings in the above diagram:

  1. Line AB is a horizontal line.
  2. Line CD is a vertical line.
  3. If Line CD had met line AB at another angle; lets say at angle 45o, then we can correctly say that line CD meets line AB obliquely.
  4. Please read on Trigonometry, Sine, Cosine and Tangent here.


4.Parallel Line

Two lines are considered to be parallel if they will never meet each other, no matter the length at which you extend them.

The diagram below show two parallel lines:

Parallel Lines - Len Academy


5. Oblique Line

Oblique lines are neither perpendicular nor parallel. They are slanted or tilted lines that will finally meet at some point, but not at a right angle (90o).

Oblique Lines - Len Academy

In the diagram above, the lines in:

  • Figure 1 is oblique
  • Figure 2 is perpendicular
  • Figures 3 and 4 are parallel

Note: Oblique lines are sometimes referred to as slanting lines.


  • Curved line

Curved Line - Len Academy

When the path between two lines isn’t straight, then such line can be said to be curved. Below is a curved line.

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Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.

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Amazing facts in Mathematics

The opposite sides of a 🎲 dice 🎲 will always give a sum of seven

31,556,926 seconds makes one year

From 0 through 1000, the only number that has the letter 'a' in it is 'one thousand'


The division symbol '÷' is actually called an obelus

Four is the only number in the English language that is spelt with the same number of letters as the number (4) itself

40 is spelt as FORTY and not FOURTY. It is the only number that is spelt with letters arranged in alphabetical order 🙄

An odd number is a number that cannot be divisible by 2.

Every odd number has an 'e' in its spelling. They include:

  • One
  • Three
  • Five
  • Seven
  • Nine

555 in Thailand should sound like 'hahaha'. This is because the word '5' means 'ha' in Thailand

10! Actually means 10 factorial in mathematics. Below is its calculation:

10! = 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 3628800

3628800 seconds is the same as 42 days

42 days is the same as 6 weeks

We can therefore say that 10! equals 6 weeks or 3628800 seconds in mathematics

When you multiply 111,111,111 by 111,111,111; the result equals 12,345,678,987,654,321


Sides of a right angle triangle - Len Academy


The image above shows a right angled triangle. The angle of the above right triangle is denoted as θ


Hypotenuse is always the longest side of the triangle.

Opposite is the side opposite the angle (θ)

Adjacent is the shorter side next to the angle (θ)

Each of Sin θ, cos θ and tan θ are the ratio of sides of the right triangle. They are calculated by using the formula (margic word) sohcahtoa:

Sohcahtoa - Len Academy


Sin θ = Opposite/Hypotenuse


Cos θ = Adjacent/Hypotenuse


Tan θ = Opposite/Adjacent

Please read more on sine, cosine and tangent here

Circumference in mathematics means the distance around the edge of a circle (or a another curverd surface).

Perimeter means the distance around a square or rectangle or polygon.

Circumference is to circle or any other curved surface

Circumference of a Circle - Len Academy

Perimeter is to square or rectangle or polygon

Perimeter of a Rectangle - Len Academy