## Did you know?

We also have Bitesize study guides covering many subjects at National 4 and National 5 on our Knowledge & Learning BETA website.

Home > Maths I > Relationships > Formulae

Maths I

Formulae

# Constructing a formula (continued)

In the diagram below the pattern with triangle needs rods. The pattern with triangles needs rods.

Try to answer the following questions using the diagram above.

Question

How many rods are needed for the pattern with triangles?

rods

Question

Complete the table for the number of rods needed for different numbers of triangles.

Number of triangles (T)

123456

Number of rods (R)

35

The second row of the table should read 3, 5, 7, 9, 11, 13.

Number of triangles (T)

123456

Number of rods (R)

35791113
Question

Write down a formula for the number of rods,, needed in a pattern with triangles.

is rising by each time. This suggests the times table which gives , , , , , . Add to get the numbers in the table.

So the formula is

Question

How many rods are needed for a pattern with triangles?

rods.

Question

How many triangles are there in a pattern using rods?