A line which is not prepared a curve is known as straight line.

As we know that the equation of **straightline** is generally in the form of:

Y = mx + b; or

Y = mx + c;

Where ‘m’ is the slope (gradient) of a line, slope and gradient both are same term.

And ‘b’ is the y- intercept.

Now we will see how to find the value of ‘m’ and ‘b’;

If we want to find the value of ‘b’ then we need to find where the line intersects the y- axis. Than we are find the value of ‘m’:

We know that ‘m’ is the slope of line, and then the value of ‘m’ is:

m = Change in y,

Change in x

Suppose change in ‘y’ is 5 and change in ‘x’ is 2 then we can find the value of ‘b’ and slope of a line;

We know that slope of line is:

m = Change in y,

Change in x

So put the value in the given formula:

m = 5

2

So the slope of the line is 5 and the value of b is 2.

So the equation of line by putting the value of slope and b is:

We know that the equation of line is:

Y = mx + b;

Put value of slope and y- intersect we get the equation of line.

Y = 5x + 2;

Now we will see slope of the straight line.

Suppose the coordinates of a straight line is p_{1}, p_{2} and q_{1}, q_{2} and ‘m’ is the slope of a line, and then we use following formula for finding the slope of a straight line.

m = q_{1} – q_{2,}

p_{1} – p_{2}

Suppose we have the values of coordinates is (3, 6) and (7, 9), then by using these coordinates find the slope of a line.

We know that the slope of a straight line is:

m = y_{1} – y_{2},

x_{1} – x_{2}

Now put the values of these coordinates we get:

m = 6 – 9,

3 – 7

So the slope of a straight line is:

m = -3

-4

So the slope of line is 0.74.

As we know that the **radius of a circle** is 2πr, by using this formula we can find out the Radius of a Circle. **ICSE board sample papers for class 12** are very useful for exam point of view.