A poster is to have a total area of 125 cm2. There is a margin round the edges of 6 cm at the top and 4 cm at the sides and bott
2 answers:
Answer:
The correct answer is 15 cm.
Step-by-step explanation:
Let the width of the required poster be a cm.
We need to have a 6 cm margin at the top and a 4 cm margin at the bottom. Thus total margin combining top and bottom is 10 cm.
Similarly total margin combining both the sides is (4+4=) 8 cm.
So the required printing area of the poster is given by {( a-10 ) × ( a - 8) }
This area is equal to 125 as per as the given problem.
∴ (a - 10) × (a - 8) = 125
⇒ - 18 a +80 -125 =0
⇒ - 18 a -45 = 0
⇒ (a-15) (a-3) = 0
By law of trichotomy the possible values of a are 15 and 3.
But a=3 is absurd as a 4.
Thus the required answer is 15 cm.
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The first two steps work for solving large perfect squares as well.
1. Divide your number into perfect square factors.
2. Take the square roots of your perfect square factors.
3. If your number doesn't factor perfectly, reduce your answer to simplest terms.
4. If needed, estimate. In some cases if you have memorized some of the square roots, you can estimate where the number would be.
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you know that 
and 
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5. <span>Alternatively, reduce your number to its lowest common factors as your first step.</span><span> Finding perfect square factors isn't necessary if you can easily determine a number's prime factors (factors that are also prime numbers).
ie. </span>
=
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Hope this helped!!!
The first two steps work for solving large perfect squares as well.
1. Divide your number into perfect square factors.
2. Take the square roots of your perfect square factors.
3. If your number doesn't factor perfectly, reduce your answer to simplest terms.
4. If needed, estimate. In some cases if you have memorized some of the square roots, you can estimate where the number would be.
ie.
5. <span>Alternatively, reduce your number to its lowest common factors as your first step.</span><span> Finding perfect square factors isn't necessary if you can easily determine a number's prime factors (factors that are also prime numbers).
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Hope this helped!!!