MATH! PLEASE REPLY ASAP!

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OPQRS is a regular square-pyramid whose base has sides of 7 cm. Given that the total surface area of the pyramid is 161 cm2, find its slant height.

  • pyramid -

    It's similar to the previous question.
    Start with drawing a diagram if the book did not supply one.
    O is the vertex of the pyramid.
    Let D be the centre of the rectangle PQRS, and A=centre of side PQ.

    OAD is a right triangle where OD is the height=h, and OA is the height of the slant face OPQ.

    By Pythagoras theorem, we find
    OA²=sqrt(OD²+AD²)
    =sqrt(h²+3.5²)

    Area of one slant face
    =AQ*OA
    =3.5sqrt(h²+3.5²)

    Area of 4 slant faces
    =14sqrt(h²+3.5²)

    Area of rectangular base
    =7*7
    =49

    Equate the sum of areas to total surface area
    14sqrt(h²+3.5²)+49=161

    Solve for h. I get 7.2 approx.

  • MATH! PLEASE REPLY ASAP! -

    Se the methos
    H^2= B^2+P^2

  • MATH! PLEASE REPLY ASAP! -

    answer will be 8

  • MATH! PLEASE REPLY ASAP! -

    You people are just desyroying the math. be ashame ofvyourself you cannot give correct answer of even 1 question shame on yourself

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