Answer:
Step-by-step explanation:
d = c/pi
so d = 62.8/pi
d = 62.8/pi or appr 19.99in
r = d/2
so r = 62.8/2pi or 31.4/pi appr 19.99/2

so

then

so
a = approximately 313.84
answer is rowan
You have to plug in the given numbers and perform each operation. Let me know if you have questions. The answers are circled.
Using the determinant method, the cross product is

so the answer is B.
Or you can apply the properties of the cross product. By distributivity, we have
(3i + 8j - 6k) x (-4i - 2j - 3k)
= -12(i x i) - 32(j x i) + 24(k x i) - 6(i x j) - 16(j x j) + 12(k x j) - 9(i x k) - 24(j x k) + 18(k x k)
Now recall that
- (i x i) = (j x j) = (k x k) = 0 (the zero vector)
- (i x j) = k
- (j x k) = i
- (k x i) = j
- (a x b) = -(b x a) for any two vectors a and b
Putting these rules together, we get
(3i + 8j - 6k) x (-4i - 2j - 3k)
= -32(-k) + 24j - 6k + 12(-i) - 9(-j) - 24i
= (-12 - 24)i + (24 + 9)j + (32 - 6)k
= -36i + 33j + 26k