✖️;
➗ = ✖️✖️ = ✖️=;
➕➖= 1➕➖ = 1➕=
s=ab cл. b = s:а
b = 40 : 4 = 10 см
P= 2(a+b)
P= 2 * (4 +10) =2*14=28 см