and I will gave Brainliest

320

190

318

42.241951146971

Step-by-step explanation:

9514 1404 393

Step-by-step explanation:

The area formula for a rectangular prism is ...

  A = 2(LW +H(L+W))

For (L, W, H) = (8, 8, 6) ...

  A = 2(8·8 +6(8+8)) = 2(64 +96) = 320 . . . square units

For (L, W, H), = (2, 9, 7) ...

  A = 2(2·9 +7(2 +9)) = 2(18 +77) = 190 . . . square units

For (L, W, H) = (6, 7, 9) ...

  A = 2(6·7 +9(6 +7)) = 2(42 +117) = 318 . . . square units

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The area of the triangular prism is the sum of its triangular base areas and the lateral area. The lateral area is the product of the base perimeter and the length of the prism.

  A = 2(1/2)bh +PL

  = 3(2.6) +(3+3+3)·4

  = 7.8 +9·4 = 43.8 . . . square units

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12

answer is 12345678900987654321234567890987654321

step-by-step explanation: