If the four numbers 4.5, 7.5, (1/2) and (3/10) are proportional, what is the product of the inner terms?
把4.5、7.5、(1/2)、(3/10)这四个数组成比例，其内项的积是多少．
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) * 7.5</gadget>
<output>2.25</output>

<result>2.25</result>