更新1:
___centimeters by ___ centimeters
A rectangular ink pad has a perimeter of 20 centimeters. Its area is 24 square centimeters. What are the dimensions of the ink pad?
回答 (11)
2020-05-07 1:45 am
Method 1:
Let x centimeters by (24/x) centimeters be the dimensions of the ink pad.
2 [x + (24/x)] = 20
x + (24/x) = 10
For x ≠ 0: [x + (24/x)] x = 10x
x² - 10x + 24 = 0
(x - 4)(x- 6) = 0
x = 4 or x = 6
The answer: 4 centimeters by 6 centimeters
====
Method 2:
Let x centimeters by y centimeters be the dimensions of the ink pad.
2(x + y) = 20 …… [1]
xy = 24 …… [2]
From [1]:
x + y = 10
x = 10 - y …… [3]
Substitute [3] into [2]:
(10 - y)y = 24
y² - 10y + 24 = 0
(x - 4)(x - 6) = 0
x = 4 or x = 6
Substitute the value of x into [3]:
When x = 4: y = 6
When x = 6: y = 4
The answer: 4 centimeters by 6 centimeters
Let x centimeters by (24/x) centimeters be the dimensions of the ink pad.
2 [x + (24/x)] = 20
x + (24/x) = 10
For x ≠ 0: [x + (24/x)] x = 10x
x² - 10x + 24 = 0
(x - 4)(x- 6) = 0
x = 4 or x = 6
The answer: 4 centimeters by 6 centimeters
====
Method 2:
Let x centimeters by y centimeters be the dimensions of the ink pad.
2(x + y) = 20 …… [1]
xy = 24 …… [2]
From [1]:
x + y = 10
x = 10 - y …… [3]
Substitute [3] into [2]:
(10 - y)y = 24
y² - 10y + 24 = 0
(x - 4)(x - 6) = 0
x = 4 or x = 6
Substitute the value of x into [3]:
When x = 4: y = 6
When x = 6: y = 4
The answer: 4 centimeters by 6 centimeters
2020-05-08 10:25 am
PERIMETER = 2 ( LENGTH + BREADTH ) = 20 CM
LENGTH + BREADTH = 10 CM
LET THE BREADTH BE X CM
LENGTH = 10- X CM
( 10 - X ) * X = 24 SQ CM
10X - X^2 = 24
X^2 -10X + 24=0
( X-6) ( X-4) = 0
X = 4
BREADTH = 4 CM LENGTH = 6 CM ANSWER
LENGTH + BREADTH = 10 CM
LET THE BREADTH BE X CM
LENGTH = 10- X CM
( 10 - X ) * X = 24 SQ CM
10X - X^2 = 24
X^2 -10X + 24=0
( X-6) ( X-4) = 0
X = 4
BREADTH = 4 CM LENGTH = 6 CM ANSWER
2020-05-07 1:35 am
Let L be length and W be width.
2L + 2W = 20, and LW = 24. L = 24/W.
2(24/W) + 2W = 20
48/W + 2W = 20
48 + 2W^2 = 20W.
2W^2 - 20W + 48 = 0
W^2 -10W + 24 = 0
(W - 6)(W - 4) = 0
W = 6; L =24/W = 24/6 = 4.
Dimensions are 4 and 6.
2L + 2W = 20, and LW = 24. L = 24/W.
2(24/W) + 2W = 20
48/W + 2W = 20
48 + 2W^2 = 20W.
2W^2 - 20W + 48 = 0
W^2 -10W + 24 = 0
(W - 6)(W - 4) = 0
W = 6; L =24/W = 24/6 = 4.
Dimensions are 4 and 6.
2020-05-08 10:19 am
Given
A = 24 cm^2
P = 20 cm
P = 2l + 2w
20 = 2l + 2w eq1
A = lw
24 = lw eq2
at eq2 make l as the subject.
l = 24/w
substitute l l = 24/w to eq1
[20 = 2(24/w) + 2w]w
20w = 48 + 2w^2
2w^2 - 20w + 48 = 0
w^2 - 10w + 24 = 0
(w - 4)(w - 6) = 0
w = 4, w = 6
solving its length from eq2.
when w = 4
l = 24/4 = 6 cm
when w = 6
l = 24/6 = 4 cm
4 centimeters by 6 centimeters ....//
AnswerSave
A = 24 cm^2
P = 20 cm
P = 2l + 2w
20 = 2l + 2w eq1
A = lw
24 = lw eq2
at eq2 make l as the subject.
l = 24/w
substitute l l = 24/w to eq1
[20 = 2(24/w) + 2w]w
20w = 48 + 2w^2
2w^2 - 20w + 48 = 0
w^2 - 10w + 24 = 0
(w - 4)(w - 6) = 0
w = 4, w = 6
solving its length from eq2.
when w = 4
l = 24/4 = 6 cm
when w = 6
l = 24/6 = 4 cm
4 centimeters by 6 centimeters ....//
AnswerSave
2020-05-07 8:38 am
2l + 2w = 20
==> l+w = 10
==> l = 10-w
...l*w = 24==> w(10-w) = 24==> 10w - w^2 = 24==> w^2 -10w + 24 = 0==> (w-4)(w-6) = 0==> w = 4 or 6 cmand l = 6 or 4 cmSo, 6 by 4 cm
==> l+w = 10
==> l = 10-w
...l*w = 24==> w(10-w) = 24==> 10w - w^2 = 24==> w^2 -10w + 24 = 0==> (w-4)(w-6) = 0==> w = 4 or 6 cmand l = 6 or 4 cmSo, 6 by 4 cm
2020-05-07 6:32 am
Area = Length x Width
A = L X W
If the area is 24, you have to figure out what 2 numbers multiplied = 24
1 x 24
2 x 12
3 x 8
4 x 6
Perimeter = lenght + width + length + width
Perimeter = 2 length + 2 width
P = 2L + 2W
now draw a rectangle and plug these numbers in to find the perimeter 24
the first option is wrong because you already see 24 and if you add them up it will go higher than 20
2 + 2 + 12 + 12 = 28
3+3+8+8 =22
4+4+6+6 = 20 bingo, so your length and your width are 4 and 6!
the rule of perimeter that i gave is only valid for a rectangle or square
do not use this rule for other shapes
The answer is 4x6
A = L X W
If the area is 24, you have to figure out what 2 numbers multiplied = 24
1 x 24
2 x 12
3 x 8
4 x 6
Perimeter = lenght + width + length + width
Perimeter = 2 length + 2 width
P = 2L + 2W
now draw a rectangle and plug these numbers in to find the perimeter 24
the first option is wrong because you already see 24 and if you add them up it will go higher than 20
2 + 2 + 12 + 12 = 28
3+3+8+8 =22
4+4+6+6 = 20 bingo, so your length and your width are 4 and 6!
the rule of perimeter that i gave is only valid for a rectangle or square
do not use this rule for other shapes
The answer is 4x6
參考: 3rd grade math
2020-05-07 5:46 am
4 centimeters by 6 centimeters.
2020-05-07 4:05 am
6 centimeters by 4 centimeters
2020-05-07 2:44 am
Nearly equal factors of area 24 are 4*6
That works with 2(4 + 6) so answers were by inspection
That works with 2(4 + 6) so answers were by inspection
2020-05-07 2:10 am
4cm by 6cm=
P=4+4+6+6=20
A=4 * 6 = 24
P=4+4+6+6=20
A=4 * 6 = 24
2020-05-07 1:32 am
A rectangular ink pad has a perimeter of 20 centimeters.
Its area is 24 square centimeters.
What are the dimensions of the ink pad?
The length is 6 cm and the width is 4 cm.
Its area is 24 square centimeters.
What are the dimensions of the ink pad?
The length is 6 cm and the width is 4 cm.
收錄日期: 2021-04-18 18:29:05
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