Learn Class 11 Math - Lines and Angles

In mathematics, a straight line is defined as a line followed by a point travelling in a constant direction with no curvature. Straight lines connect two points shortest distance.

Lines can be divided into many types, such as horizontal, perpendicular, vertical, and parallel.

Lines

Horizontal line

When a line moves from east to west, it is horizontal.

Perpendicular line

When any two lines meet each other at an angle of 90° is called a perpendicular line.

Vertical line

A straight line from up to down is called a vertical line.

Parallel line

When any two lines don't meet, touch, or intersect even at infinity, that line is called a parallel line.

Tangent

A straight line that touches the curve is called a tangent at any given point.

Angles

An angle is formed when two rays are united at a common point. An angle is usually measured in degrees, radians, or gradians.

  • Acute angles are formed between 0° to 90°.
  • An obtuse angle is formed between 90° to 180°.
  • An angle equal to 180°>is called a straight angle.
  • Reflex angles are greater than 180° and less than. 360°.
  • And an entire rotation of an angle leads to 360°.

Lines and Angles Sample Questions for Class 11

Question 1

A polygon that is always convex.
A. Triangle
B. Quadrilateral
C. Circle
D. N-gon

Question 2

What is the reference angle for (7 pi) /4 ?
A. pi/4
B. pi/3
C. pi/6
D. (3pi)/4

Question 3

If two sides of a parallelogram are 4 inches and 8 inches in length, and have a 30^@ angle between them the area of the parallelogram is
A. 32 sq in.
B. 16sqrt3 in.
C. 16 sq in.
D. none of these.

Question 4

Beginning from the positive side of the x-axis, rotating around in the clockwise direction creates a positive angle.
A. True
B. False

Question 5

A square pyramid sculpture contains 50 \ "ft"^3 of granite and is 6 feet high. What is the area of the base of the sculpture?
A. 5 \ "ft"
B. 25 \ "ft"
C. 5 \ "ft"^2
D. 25 \ "ft"^2