Answer:

Step-by-step explanation:







Hello from MrBillDoesMath!
Answer:
75
Discussion:
A plane triangle has 180 degrees. Using this in the diagram gives
x + 81 + angle BAC = 180 (***)
(The diagram is a bit fuzzy but I think the above numbers are accurate)
The diagram also shows that (156 + angle BAC )= 180 as a straight line has 180 degrees. So
angle BAC = 180 - 156 = 24
Substituting this in (***) above gives
x + 81 + 24 = 180 =>
x + 105 = 180 => (as 81 + 24 = 105)
x = 180 107 = 75
Check: Does
x + 81 + angle BAC = 180 ?
75 + 81 + 24 = 180. Yes
Thank you,
MrB
Let
. The gradient of
at the point (1, 0, 0) is the normal vector to the surface, which is also orthogonal to the tangent plane at this point.
So the tangent plane has equation

Compute the gradient:

Evaluate the gradient at the given point:

Then the equation of the tangent plane is
