Since the opposite side of the quadarilateral are equal hence it is a rectangle.
Perimeter of a rectangle
The sum of the external side is equal to the perimeter. The perimeter of the shape is expressed as:
P = 2(l+w)
where:
P = 120cm
If the width is 30cm less than twice it’s length, then;
w = 2l + 30
Substitute
120 = 2(l + 2l + 30)
60 = 3l + 30
3l = 30
l = 10
Recall that:
w = 2l + 30
w = 2(10) + 30
w = 50cm
Since the opposite side of the quadarilateral are equal hence it is a rectangle.
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