The given equation of line is
Which is of the form
Where m is the slope which is 3 here.
And slope of parallel lines are equal. So slope of the required line is 3 too .
Now we use slope intercept form, and plug the values of the slope and the given point and solve for b, that is
So we have m =3 and b=4. Therefore required equation of line is
Let's use the line on the right side. In the smaller triangle, the length is 4. The same side on the bigger triangle is 12. The ratio of the smaller triangle to the bigger triangle is:
To find a side length for the bigger triangle, all you need to do is multiply by 3. The same side on the smaller triangle is 5. Multiply by 3
That means x = 15
Try this suggested example.
PS. the 1st step is marked with red, the 2d step - with green, the 3d step - with blue colours, then the final step is marked with orange.
