# Perimeter and area

Most perimeter and area questions at National 5 are set in problem situations.

### Example

A garden is in the shape of a rectangle measuring $$16.3m$$ by $$12.4m$$.

The gardener marks out the two diagonals and decides to sow grass seeds on one of the four triangles formed by the intersection.

The seed packet states that $$30\,g$$ of seed are recommended per square metre.

What weight of seed will he need?

The area of the shaded triangle can be worked out as either $$\frac{1}{4}\,\,\times16.3\,\times\,12.4 = 50.53\,m^{2}$$ (based on dividing the area of the rectangle by four) or $$\frac{1}{2}\,\,\times16.3\,\times\,6.2 = 50.53\,m^{2}$$ (based on $$\frac{1}{2} \times base \times height$$ where the height is half of $$12.4m$$).
Weight of seed recommended $$=50.53\,\times 30 = 1515.9\,g$$