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Home > Maths I > Relationships > Direct variation

Maths I

Direct variation

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# Finding the variation formula (continued)

## Example

Study this worked example carefully before doing the questions.

The cost, , of producing a booklet varies directly as the square root of the number of pages it contains.

A booklet with pages costs to produce.

Find the cost of producing a booklet with pages.

Therefore

so,

()

is the variation formula

for a booklet with 100 pages

Therefore

The cost is

### Now try these questions.

Question

varies directly as the square root of

when

Find when

Variation formula is

Question

varies directly as the square of .

when

Find when

Variation formula is

Question

The value, , of a diamond varies directly as the square of its weight, carats.

A diamond weighing carats is worth .

Find the value of a diamond weighing carats.

Variation formula is

Value is

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