7.
1/1 points 
Previous Answers
(a) Let
P
be a point not on the line
L
that passes through the points
Q
and
R
. Show that the
distance
d
from the point
P
to the line
L
where
and
Nothing to enter for (a); after submitting your answer for (b) check your work against the
answer key
.
(b) Use the formula in part (a) to find the distance from the point
P
(1, 1, 1) to the line through
and
Thus the
distance is
d
=

a
×
b


a
a
=
QR
b
=
.
Q
(0,
9
,
7
)
R
(−1,
2
,
is
Solution or Explanation
is

QP
6
).
PS
QP
b


a

−6
.
QP
15
.
1430
51
5/6
1399
HW #4
6/6