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Math Help - Help With A Grid

  1. #1
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    Help With A Grid

    Please Help With This. I Attachments
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by dgenerationx2 View Post
    Please Help With This. I Attachments
    Looks like this to me:

    Rectangular portion below first roof angle is 5 X 8 minus the doors (6) = 34 squares

    From first roof angle to second roof angle we have a trapezoid with bases 8 and 4 with height 1.

    Using A=\frac{1}{2}h(b_1+b_2), we can find the area of the trapezoid to be 6 squares

    The remaining portion is a triangle with base 4 and height 4. Using A=\frac{1}{2}bh, we find the area of the triangle to be 8 squares.

    That makes a total of 48 squares X 9 square feet per square = 432 square ft.
    Last edited by masters; October 31st 2008 at 10:57 AM. Reason: Mis-read the square footage of each square. Changed to 9 square feet instead of 3 square feet.
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  3. #3
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    Hello, dgenerationx2!

    I must assume you are familiar with basic area formulas:
    . . area of a triangle, area of a rectangle.
    Then exactly where is your difficulty?


    The front of the building below need to be repainted.

    How many square feet will need to be repainted, excluding the door?
    Code:
          -                 *
          :                *|*
          :               */|/*
          :              *//|//*
          1             *///|///*
          :            *////|12//*
          :           */////|/////*
          :          *//////|//////*
          -       . *-------*-------* .
          2   . *///////////|3//////////* .
          - *-------*-------*-------*-------*
          : |///6///////6///////6///////6///|
          : |///////////////////////////////|
          : |///////////////////////////////|
          3 |///////////////////////////////| 15
          : |///////////* - - - *///////////|
          : |///////////|   6   |///////////|
          : |///////////|9      |///////////|
          : |///////////|       |///////////|
          - *-----------*-------*-----------*
            : - - - - - -  24 - - - - - - - :

    Level 1: An isosceles triangle with base 12 and height 12.
    . . Its area is: . \tfrac{1}{2}(12)(12) \:=\:72 ft².

    Level 2: A trapezoid with bases 12 and 24, and height 3.
    . . Its area is: . \tfrac{3}{2}(12 + 24) \:=\:54 ft².

    Level 3: A 24×15 rectangle minus a 6×9 rectangle.
    . . Its area is: . (24\cdot15) - (6\cdot9) \:=\:360 - 54 \:=\:306 ft².


    The total area is: . 72 + 54 + 306 \;=\;{\color{blue}432\text{ ft}^2}


    Ha! . . . masters beat me to it!
    .
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