<h2><em>Answer:</em></h2><h2><em>=</em><em>12</em></h2><h2><em>12step</em><em> </em><em>by step explanation:</em></h2><h2><em>=</em><em>solution:</em></h2><h2><em>solution:area of gym=144</em></h2><h2><em>solution: area of gym= 144we know that,</em></h2><h2><em>solution: area of gym= 144we know that,area of square=L²</em></h2><h2><em>solution: area of gym= 144we know that, area of square= L²or,144=L²</em></h2><h2><em>solution: area of gym= 144we know that, area of square= L² or,144= L²or,(12)²=L²(12²means 12×12=144)</em></h2><h2><em>solution: area of gym= 144we know that, area of square= L² or,144= L² or, (12)² = L²(12² means 12×12=144)or,12=L</em></h2><h2><em>solution: area of gym= 144we know that, area of square= L² or,144= L² or, (12)² = L²(12² means 12×12=144) or, 12= L therefore,L =12</em></h2>