A side of an isosceles triangle is (2/5) decimeters long, and its base is (3/10) decimeters longer than the waist. What is the perimeter of this triangle in decimeters.
等腰三角形的一条腰长是(2/5)分米，它的底边比这条腰还长(3/10)分米．这个三角形的周长是多少分米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) + (3/10) + (2/5) + (2/5)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>