A square log with a square cross section has a perimeter of 28 decimeters and the length of the square log is 5 meters. If the mass of wood per cubic meter is 0.45 tons, what is the mass of this square log?
一根横截面是正方形的方木，横截面的周长是28分米，方木长5米．如果每立方米木头的质量是0.45吨，这根方木的质量是多少吨？
<gadget id="calculator">28 / 4 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">(7/10) * (7/10) * 5 * 0.45</gadget>
<output>1.1025</output>

<result>1.1025</result>