CPhill

Mr.Henry is painting a square floor of side 36m. He divided the floor into 12 equal sections.

A.He painted 4 sections. What percentage of the floor is painted?

B.Calculate the area of the floor?

C. What area of the floor is not painted.Give answer in sp metres.

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A. 33% .......(4 sections represent 1/3 of the total = 33%)

B. Area of floor = 36m X 36m = 1296 sq meters

C. If 1/3 is painted, 2/3 must not be. So, 2/3 x 1296 = 864 sq meters !!

s √2+√2 = 2√2 or √4

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This kind of stuff use to confuse me, too.  Here's a hint....when confronted by something that you're not sure of .... use some numbers that you know and see if this leads you to the correct answer !!

For instance ......is √9+√9 = 2√9 or √18   ???

Well....√9+√9 = 3 + 3 = 6

And....... 2√9 = 2*3 = 6

Mmmmm...that looks a lot like the first answer, doesn't it??

Think about √18.....the √16 = 4 and the √25 = 5...so the √18 must be between 4 and 5 and that's certainly < 6 !!

Can you answer your own question, now??

Alan's answer is correct.....Here's a slightly different approach

I first put "g" into "f"

So we have.....

-2(-4x + 6) - 7    =

8x - 12  - 7  =

8x - 19

Now, put the (-5) into this "composite" function

We have:

8(-5) - 19   =

-40 - 19  =

-59

Either approach works...your choice!!

We have

80 - (-35)

Remember that a negative outside parentheses or brackets changes the sign of everything inside....so we have

80 + 35 = 115

Bill Ding constructs quality homes. He figures that a house built on a particular lot should be sold for 373,000 if it has a floor space of 3000 square feet. A 4000 square foot house constructed on the same lot should be sold for 483000. The selling price is the sum of the construction cost, at a fixed number of dollars per square foot, and the cost of the lot. Figure out the number of dollars per square foot it costs to construct the house, and the cost of the lot

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OK.....we just need a linear equation here...I'm going to represent these numbers in thousands just to simplify the process. Let square feet be the"x" variable and total cost be the "y" variable.

So we have the points (3, 373) and (4, 483)....to write a linear equation, we need to find the slope of our line.  We have

(483 - 373) / (4 - 3) = 110   (This actually is the cost per sq ft = $110)

So, using a point and the slope we have.....

y - 373 = 110 (x - 3)

y = 110x + 43  or

y = 110x + 43000

So, the lot cost must just be $43000

Chek this with the $483000 house...

y = 110(4000) + 43000

y = $483000

P.S.....I like the "Bill Ding" thing !!!

what is sin7? and how do you do it

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We have to be careful, here. Without the "degree" symbol, this means .....finding the sine of an angle with a measure of 7 rads !!! This (in degrees) is about

$${\frac{{\mathtt{7}}{\mathtt{\,\times\,}}\left({\mathtt{180}}\right)}{{\mathtt{\pi}}}} = {\mathtt{401.070\: \!456\: \!591\: \!576\: \!246\: \!1}}$$   

Thus, sin(7) = 0.656986598719

But, sin(7°) = 0.121869343405

See the difference....???

Re: what is 3.2*10 to the negative 7th

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I'm assuming that you have something in scientific notation like this......

3.2 X 10^-7 ....     this tells us to move the decimal 7 places to the left  ..  so we have

.00000032

And that's it !!!

Re: What is the height of a rectangle with a perimeter of 216 mm and a base length of 44 mm?

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Let's look at this one again....

Perimeter = 2(B + H)  Substituting, we have

216 = 2(H + 44)  divide by 2 on each side

108 = H + 44   subtract 44 from both sides

108 - 44 = H

H = 64 cm

HELP ME! h=at-0.25vt^2, solve for a!

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OK    So we have

h = at -.25vt²    Here's the easiest war to do this...add .25vt² to each side

h + .25vt² = at    Now, divide by t    This gives

(h + .25vt²) / t   = a

And that's it !!  Not too bad, huh??

I've never seen this method before, but after reading about it, it seems like an easy way to perform "long" division. Thanks, Anonymous....I'll be giving you a "thumbs-up" for that one !!!