The side length of a square farmland is 200 meters. To fertilize this farmland, calculate the fertilization rate of 105 kilograms per hectare. How many kilograms of fertilizer should be applied in total?
一块正方形农田的边长是200米，给这个农田施肥，按每公顷施肥105千克计算，一共应施肥多少千克？
<gadget id="calculator">4 * 105</gadget>
<output>420</output>

<result>420</result>