# Substitute into common formulae

## Interactive practice questions

The perimeter of a triangle with sides of length $x$x, $y$y and $z$z is given by the formula $P=x+y+z$P=x+y+z.

Find $P$P if the lengths of its sides are $x=6$x=6 cm, $y=3$y=3 cm and $z=7$z=7 cm.

Easy
Less than a minute

The perimeter of a square with side lengths of $a$a is given by the formula $P=4\times a$P=4×a.

Find $P$P if the length of each side is $5$5 cm.

The perimeter of a rectangle is given by the formula $P=2\times\left(l+w\right)$P=2×(l+w) , where $l$l is the length and $w$w is the width.

If the width of a rectangle is $10$10 cm and its length is $5$5 cm, find its perimeter.

The area of a rectangle is given by the formula $A$A$=$=Length$\times$×Width.

If the length of a rectangle is $2$2 cm and its width is $3$3 cm, find its area.