Review question

# What's the distance from a point to a line in the $x\text{-}y$ plane? Add to your resource collection Remove from your resource collection Add notes to this resource View your notes for this resource

Ref: R9702

## Question

Show that the perpendicular distance of the point $(h,k)$ from the straight line $x\cos\alpha+y\sin\alpha=p$ is the numerical value of $h\cos\alpha+k\sin\alpha-p.$ [“Numerical value” means ignoring whether it is positive or negative, that is, the absolute value of this expression.]

Calculate the coordinates of the centres of the two circles of radius $5$ which pass through the point $(4,4)$ and touch the straight line $3x-4y-28=0$.