The perimeter of a rectangle is 108cm. The ration of its length to its width is 7:2 what is the area of the rectangle in cm2?
1 answer:
Answer:
504 cm²
Step-by-step explanation:
Let the length and the width of the rectangle be L cm and W cm respectively.
Perimeter= 2(L +W)
2(L +W)= 108
L +W= 108 ÷2
L +W= 54
L= 54 -W -----(1)
<em>Cross multiply:</em>
2L= 7W -----(2)
Substitute (1) into (2):
2(54 -W)= 7W
<em>Expand:</em>
108 -2W= 7W
<em>+2W on both sides:</em>
9W= 108
<em>Divide both sides by 9:</em>
W= 108 ÷9
W= 12
<em>Substitute W= 12 into (1):</em>
L= 54 -12
L= 42
Area of rectangle
= length ×width
= LW
= 42(12)
= 504 cm²
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Option C:
The last two terms given of the standard polynomial are:
This shows 2 patterns to us:
r 's degree is increasing per term in the given polynomial.
s 's degree is decreasing per term in the given polynomial.
The sum of powers of variates r and s is 2+4 = 3+3 = 6.
And since standard polynomial, the same pattern must be present in all terms of the series.
All options except C are not valid.
Option C has term for which r's degree plus s's degree is 1 + 5 = 6.
And r's degree 1 < s's degree 5.
Thus its a valid term to be putted as first term in standard form of polynomial in consideration.
Thus Option C: is the needed expression.
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