Problem

A student is solving the proportion \(6/9~=~x/15\).

Their work is shown below:
\(6/9~=~x/15\)
\(6~\cdot~15~=~9~\cdot~x\)
\(90~=~9x\)
\(x~=\)

Complete the missing final value.

Vertical work sample for solving a proportion. It shows 6 over 9 equals x over 15, then 6 times 15 equals 9 times x, then 90 equals 9x, and the last line shows x equals a blank box.

Big Picture

What this problem is really about

The displayed cross multiplication is already complete, so the task is to finish the ordinary equation ninety equals nine x. We’ll isolate x by dividing both sides by the coefficient nine, rather than copying a number from the original proportion. Substitution will let us reduce both ratios and confirm the missing final value.

Answer choices

Choose your path.

Preview only

The choices are visible. Checking your work and seeing which answer is correct happen inside Gozunta.

A student is solving the proportion \(6/9~=~x/15\).

Their work is shown below:
\(6/9~=~x/15\)
\(6~\cdot~15~=~9~\cdot~x\)
\(90~=~9x\)
\(x~=\)

Complete the missing final value.

What this problem is really about

Turn the preview into practice.

Gozunta lets you study this problem—and more than 10,000 others.

A student is solving the proportion \(6/9~=~x/15\).Their work is shown below:\(6/9~=~x/15\)\(6~\cdot~15~=~9~\cdot~x\)\(90~=~9x\)\(x~=\) Complete the missing final value.

What this problem is really about

Turn the preview into practice.

Gozunta lets you study this problem—and more than 10,000 others.

A student is solving the proportion \(6/9~=~x/15\).

Their work is shown below:
\(6/9~=~x/15\)
\(6~\cdot~15~=~9~\cdot~x\)
\(90~=~9x\)
\(x~=\)

Complete the missing final value.