please fill in the blanks using javascript

Zach Stern, a floor tiler doing business as Zach Stern's Tile, needs to know the area of any rectangular floor he's tiling. He wants a program that asks for the room's length and width and the cost per square foot of tile. The program should calculate and display the room's area in square feet and the cost of the tile needed to cover the room. let length = (prompt ("Enter length of room")); let width = (prompt ("Enter width of room")); let costPerSqFt - ( prompt ("Enter cost per square foot')); sqFeet totalCost - ("The room is " + +" square feet. At " + +" per sq.ft., It will cost " + + " to tile it."); Expected Output: >>The room is 300 square feet. >>At 25 per sq.ft. It will cost 7500 to tile it