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3 years ago

Find the area of the rectangle 2 1/2cm 4cm

Mathematics

1 answer:

Neporo4naja [7]3 years ago

5 0

2.5•2.5= 5 , 4•4=8 , 8+5=12

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A square building with an area of 225 m2 has a garden surrounding it that has an equal width on all sides. The area of the garde

xenn [34]

Answer:

The width of the garden is 1.16 m

Step-by-step explanation:

step 1

<em>Find the area of the garden</em>

To find out the area of the garden multiply by 1/3 the area of the building

$225(\frac{1}{3})=75\ m^2$

step 2

Find the length side of the square building

The area of a square is

$A=b^2$

where

b is the length side of the square

we have

$A=225\ m^2$

$b^2=225\\b=15\ m$

step 3

Find the width of the garden

Let

x ----> the width of the garden

we know that

The area of the building plus the area of the garden is equal to

$(15+2x)^2=225+75$

solve for x

$225+60x+4x^2=225+75\\4x^2+60x-75=0$

Solve the quadratic equation by graphing

using a graphing tool

The solution is x=1.16 m

see the attached figure

therefore

The width of the garden is 1.16 m

Find the exact value

The formula to solve a quadratic equation of the form $ax^{2} +bx+c=0$

is equal to

$x=\frac{-b\pm\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$4x^2+60x-75=0$

$a=4\\b=60\\c=-75$

substitute in the formula

$x=\frac{-60\pm\sqrt{60^{2}-4(4)(-75)}} {2(4)}$

$x=\frac{-60\pm\sqrt{4,800}} {8}$

$x=\frac{-60\pm40\sqrt{3}} {8}$

$x=\frac{-60+40\sqrt{3}} {8}\ m$ ----> exact value

8 0

3 years ago

Please help me please

balu736 [363]

Answer:

Step-by-step explanation:

2n + 8.5 = 23

2n = 14.5

2n = 7.25 or 7 1/4 feet

3 0

3 years ago

Find the probability that a point chosen at random will lie in the shaded area.

son4ous [18]

I think the answer is D

6 0

3 years ago

Which of the following relationships is a direct variation?

mafiozo [28]

Answer:Well All i know is that the answer is not C I'm sorry I dont know the correct answer but I know for a fact that the answer isn't C

Step-by-step explanation:

4 0

4 years ago

The sum of 30 times (1/3)^(n-1) from 1 to infinity

sergeinik [125]

Let

$S_n=\displaystyle1+\frac13+\frac1{3^2}+\cdots+\frac1{3^n}$

Then

$\dfrac13S_n=\displaystyle\frac13+\frac1{3^2}+\frac1{3^3}+\cdots+\frac1{3^{n+1}}$

and

$S_n-\dfrac13S_n=\dfrac23S_n=1-\dfrac1{3^{n+1}}\implies S_n=\dfrac32-\dfrac1{2\cdot3^n}$

and as $n\to\infty$ , we end up with

$\displaystyle\lim_{n\to\infty}S_n=\lim_{n\to\infty}\sum_{i=1}^{n+1}\frac1{3^{i-1}}=\lim_{n\to\infty}\left(\frac32-\frac1{2\cdot3^n}\right)=\frac32$

So we have

$\displaystyle\sum_{n=1}^\infty30\left(\frac13\right)^{n-1}=30\cdot\frac32=45$

8 0

3 years ago