EmanuelMarcos1572
10.11.2019 •
Mathematics
Answer questions 17,49, and ! i give
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Answers on questions: Mathematics
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Ответ:
Ответ:
Let ...
l be the length
w be the width
A be the area
As it states, the length is 4 times the width so we can write this as 4w. Next, we need to know the formula for the area of a rectangle. The formulas is this:
A = l × w
Next, we simply SUBSTITUTE the value for l into the formula to find the area and that will allow us to solve for w. We know that the area is 80cm so we can just write that,
80 = (4w)(w)
Now let's solve for w.
Step 1: Simplify both sides of the equation.
80=4w^2
Step 2: Subtract 4w^2 from both sides.
80−4w^2=4w^2−4w^2
−4w^2+80=0
Step 3: Subtract 80 from both sides.
−4w^2+80−80=0−80
−4w^2=−80
Step 4: Divide both sides by -4.
−4w^2/−4=−80/−4
w^2=20
Step 5: Take square root.
w=√20
w = ~4.5 (rounded to tenth)
now that we know w we can solve for l.
remember... l = 4w
l = 4(4.5)
l = 18
we can check this by calculating the area where l is 18 and w is 4.5.
A = l × w
A = 18 × 4.5
A = 81 ( should be 80 but we rounded)
Ответ: