The perimeter of a rectangle is length + length + width + width.
We know that the length of a rectangle is 3cm more than its width, which gives us the equation: (l for length and w for width)
l = 3 + w
We also know that the perimeter of the rectangle is 98cm, which gives us the equation:
98 = 2l + 2w (equation for perimeter of a rectangle as noted above)
We can divide both sides of this equation by 2 to get:
49 = l + w
Now we'll stick l = 3 + w into the above equation, which gives us:
49 = 3 + w + w
which simplifies to 49 = 3 + 2w.
Now we'll subtract 3 from both sides:
49 - 3 = 46
3 + 2w - 3 = 2w
which gives us 46 = 2w.
Dividing both sides by 2 gives us 23 = w.
Substituting w = 23 into the equation l = 3 + w gives us:
l = 3 + 23
l = 26cm.
Let's check our answer. 26cm is 3cm more than 23cm. 26cm + 26cm + 23cm + 23cm gives us 98cm. The length is 26cm and the width is 23cm.