The perimeter is 24cm
The surface area of a box 15cm x 12cm x 8 cm is 2 times 15cm times 12cm, plus 2 times 15cm times 8 cm, plus 2 time 12cm times 8 cm, or 792cm2. However, this is only the surface area - the actual wrapping paper required would depend on the method of wrapping and how much overlap is desired. Since you would not want to splice the paper, you certainly would need more that 792cm2 but, again, that depends on your wrapping style.
The area of rectangle is : 168.0
The area of rectangle is : 48.0
The area is ~452.3 cm2
24CM
The perimeter is 24cm
The area of a 12cm by 5cm right-angled triangle is: 42 cm2
Find the area of 5cm 12cm 8cm
We can't calculate anything regarding the rectangle, as there's a strong indication that there must be something fishy about it. A rectangle has only two dimensions, and we can't imagine what to do with the three numbers given for the rectangle in the question.
The surface area of a box 15cm x 12cm x 8 cm is 2 times 15cm times 12cm, plus 2 times 15cm times 8 cm, plus 2 time 12cm times 8 cm, or 792cm2. However, this is only the surface area - the actual wrapping paper required would depend on the method of wrapping and how much overlap is desired. Since you would not want to splice the paper, you certainly would need more that 792cm2 but, again, that depends on your wrapping style.
You cannot find the area of one unit of measurement as that is only a line, which has no area.
A square with an area of 144cm2 has sides of 12cm which is the square root of 144cm. 12cm x 12cm gives 144cm2.
12cm is the answer
The area of rectangle is : 168.0
The area of rectangle is : 48.0
The area is ~452.3 cm2