The perimeter of a rectangle = 80m. The length is decreased by 7m and the width increased by 7m

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How to find the perimeter of a figure - algebra word problem.
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22 май 2023

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Комментарии : 17

@CzJanusz Год назад

I used two variables: I think there is a simpler approach using two variables: l for length and w for width. According to the requirements of this exercise perimeter can be determined as follows: 2l + 2w = 80 Now length decreased by 7 should be equal to the width increased by 7, sin this is a square. Therefore step by step: l - 7 = w + 7 +7 +7 l = w + 14 Let us substitute l in the first equation: 2 (w + 14) + 2w = 80 /2 2w + 28 + 2w = 80 4w + 28 = 80 /4 w + 7 = 20 -7 -7 w = 20 - 7 = 13 From above l = w + 14 l = 13 + 14 = 27 Check 2 * 27 + 2 * 13 = 54 + 26 = 80

@dianemier5335 Год назад

I used the perimeter would stay 80m, so each side of the resulting square would be 20m. Length minus 7 = 20 L= 27m Width plus 7 = 20. W = 13.

@Pandemonis Год назад

Elegant, this one is even quicker.

@tomtke7351 Год назад

There are two unknowns: L -- length W -- width two unknowns requires two equations. eq.1: perimeter around rectangle; 2 lengths and 2 widths summed: eq.1: 2L + 2W = 80m eq.2: a square means length = width. or eq.2: L - 7 = W + 7 eq.1: 2L + 2W = 80m eq.2: L - 7 = W + 7 eq.2 vrevised L - 7 = W + 7 L - W = 14 2L - 2W = 28 eq.2.2 eq.1: 2L + 2W = 80m eq.2.2 2L - 2W = 28 Added together ==> 4L = 108m eq.3 L = 27 ans.1 eq.2: L - 7 = W + 7. solve with L = 27 27 - 7 = W + 7 27 - 14 = W W = 13 ans.2 VERIFY: L = 27m W = 13m eq.1: 2L + 2W = 80m eq.2: L - 7 = W + 7 eq.1: 2L + 2W = 80m 2(27) + 2(13) =? 80 54 + 26 == 80 ✔️✔️✔️ eq.2: L - 7 = W + 7 27 - 7 =? 13 + 7 20 == 20 ✔️✔️✔️

@kevingeier3385 Год назад

The rectangle is 27 by 13. Since the perimeter has not changed. A square has 4 equal side. 80 divided by 4.

@dryster123 Год назад

I did not see why it was a problem, perimeter stayed the same at 80m and it was a square, so each side was 80/4 = 20m

@michaelholcombe3336 Год назад

did it in my head in 30 sec

@quantisedspace7047 Год назад

The perimeter gets it's width and length increased and reduced in equal amounts, so the perimeters of the rect and square must be the same. The sides of the square are thus 20m. The sides of the original rect are thus 27 and 13

@monroeclewis1973 Год назад

The 80m perimeter remains the same because the 7m gain to each of the long sides of the rectangle is offset by the 7m loss to each of the short sides. The perimeter of any square is 4 times the side. Therefore, the side must be 80/4 = 20m. Working backwards, the dimensions of the original rectangle must be 20 + 7= 27m, and 20 - 7 = 13m.Just logic. No algebra.

@calvinmasters6159 7 месяцев назад

Fun way to round off an evening of bourbon. Keep 'em coming.

@gd-pythonica Год назад

The width is 13 meters and length is 27 meters. 1. Set up an equation for the perimeter that will help us solve for the sides: 2l+2w=80. 2. Set up another equation for the second clue. Since a square's sides are equal, L-7=W+7. 3. You now have a system of equations. You can solve for both variables and you will find that the width is 13m and the length is 17m.

@bobcornwell403 Год назад

The rectangle is 27 meters long and 13 meters wide.

@danieldennis9831 Год назад

I got 27 x 13

@aliso-pv7ll Год назад

Dear Mr. RU-vid Mathman, tell algebra to grow up! Solve your own problems!

@vjeraknezevic5889 Год назад

This is not right solution......process is not good

@Pandemonis Год назад

Video two long, didn't watch, its faster to make the maths by head than to type it : Given a for width and b for length, 2a + 2b = 80 Given the square information, a - 7 = b + 7, so a = b +14 so 2 (b+14) + 2b = 80 so 4b = 80 - 28 = 52, Solution for b = 13 a = 13 + 7 + 7 = 27

@vjeraknezevic5889 Год назад

Are you a teacher, what are you doing, repeating the same wrong things many time.....