. the bathroom nloor is a rectangle measuring 4m by 2m. each tile is 20cm by 20cm. how many tiles does he need?

200

Step-by-step explanation:

First, we know that 1 meter=100 centimeters, so we need to find a common measurement. Lets right it all as meters, so we dont get confused. Then we can find the total area of the floor by multiplying the too side lengths together:

400 centimeters x 200 centimeters= 80000 centimeters!

The total area of the floor is 80,000 centimeters

Now find the area of each tile:

20 centimeters x 20 centimeters= 400 centimeters

Now to find how many of those tiles can fit in that floor, we divide 80,000 by 400.

80,000/400=200

He needs 200 tiles.

Hope this helps!

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

26?

step-by-step explanation: