Answer:
x=0.4
perimeter of rectangle and perimeter of triangles is 7.6 each
Explanation:
2(7x-1.8)+2(4x+1.2)=perimeter of rectangle
6x+0.4+4x+6x+0.08=perimeter of triangle
since the perimeters are equal then
2(7x-1.8)+2(4x+1.2)=6x+0.4+4x+6x+0.8
14x-3.6+8x+2.4=16x+1.2
22x-1.2=16x+1.2
22x-16x-1.2+1.2=16x-16x+1.2+1.2
6x=2.4
x=0.4