There is a square flower bed with a side length of 15 meters in front of the community. If one group of opposite sides of the flower bed is increased by 3 meters respectively, and the length of the other group of opposite sides remains the same, how much will the area of the flower bed increase?
小区前有一个边长是15米的正方形花坛，如果把花坛的一组对边分别增加3米，另一组对边长度不变，这个花坛的面积会增加多少？
<gadget id="calculator">15 * 3</gadget>
<output>45</output>

<result>45</result>