The base of a parallelogram is 0.9 meters and the height is 4 decimeters. What is the area of a triangle with the same base and height in square meters?
一个平行四边形底是0.9米，高是4分米，与它等底等高三角形面积是多少平方米．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">0.9 * (1/5)</gadget>
<output>0.18</output>

<result>0.18</result>