In the design shown below, four semicircles are attached to a square whose area is 36 square centimeters. Which of the following is closest to the total area of the shaded semicircles, measured in square centimeters?

56.549 cm   (choice 1)

Step-by-step explanation:

If the area of the square if 36 cm, then each side is 6 cm.

That means the diameter for each semi circle is also 6 cm.

Formula for a semi circle is 1/2(πr²)

We need the radius, which is half the diameter. So the radius is 6÷2= 3

Now plug in to the formula.

A= 1/2(π3²)

A= 14.137 (nearest hundredths)

Now multiply that by 4, because there are 4 semi circles

4(14.137)= 56.549 cm (nearest hundredths)

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