Find the perimeter of the triangle?

Really need help with this! Thanks.

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2 Answers

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  • RR
    Lv 5
    4 weeks ago

    You can find two of the sides by counting the squares: 7 and 5.

    You can find the third side using Pythagoras: 

    7² + 5² = h²

    49 + 25 = h²

    74 = h²

    h = 8.6

    P = 8.6 + 7 + 5

    P = 20.6

  • Alan
    Lv 7
    4 weeks ago

    Use the distance formula for each side . 

    distance between points (x_1, y_1) and (x_2, y_2) = 

    sqrt ( (y_2 -y_1)^2  + (x_2-x_1)^2   )  

    then add them all up.

    1st side goes from (2,1) to (2,8) 

    distance side 1 =   sqrt(  (2-2)^2 + (8-1)^2 ) = 7   

    2nd side goes from (2,1) to  (7,1)  

    distance side 2 =  sqrt(  (7-2)^2 + (1-1)^2 ) =   5  

    side 3 goes from  (2,8) to (7,1)

    distance side 3 = sqrt ( (7-2)^2  + (8-1)^2 ) =

    = sqrt(   25 + 49) = sqrt( 74)  

    perimeter = 5 + 7 + sqrt(74)  

    perimeter = 20.60232527

    so the answer is (B) 

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