To calculate the value for the width of a rectangle. We need to know the basic formula for its area:

Area of a rectangle= length * width

Now lets break down our question into parts.

It is mentioned that the length of the rectangle is three times the width. Therefore we use W for width and hence:

Width=W; and

Length=3W

Now we will put in these values and the value of the area given in the area's formula to get the width:

Area=L*W

147=W*3W

147=3(W^2)

147/3=W^2

49=W^2

therefore,

W=7

Now we put this value in the formula for length that we just made. Hence:

Length=3W

=3(7)

21

To check your answer plug in the values of length and width that you just found and see if the area you get is the same as the one given in the question:

Area=Length*Width

=21*7

=147

Area of a rectangle= length * width

Now lets break down our question into parts.

It is mentioned that the length of the rectangle is three times the width. Therefore we use W for width and hence:

Width=W; and

Length=3W

Now we will put in these values and the value of the area given in the area's formula to get the width:

Area=L*W

147=W*3W

147=3(W^2)

147/3=W^2

49=W^2

therefore,

W=7

Now we put this value in the formula for length that we just made. Hence:

Length=3W

=3(7)

21

To check your answer plug in the values of length and width that you just found and see if the area you get is the same as the one given in the question:

Area=Length*Width

=21*7

=147