The distance of the point (7,10,11)(7{,}10{,}11) from the line x−41=y−40=z−23\displaystyle\frac{x-4}{1}=\frac{y-4}{0}=\frac{z-2}{3} along the line x−92=y−13−3=z−176\displaystyle\frac{x-9}{2}=\frac{y-13}{-3}=\frac{z-17}{6} is:

Answer: 26

Step-by-step solution

Step 1: Identify the given lines and point

We are given a point P(7,10,11)P(7{,}10{,}11) and two lines, L1L_1 and L2L_2. We need to find the distance from point PP to line L1L_1 measured along line L2L_2. This means we need to find the intersection point of line L2L_2 and line L1L_1, and then calculate the distance between this intersection point and point PP.

Step 2: Find the general point on line L2

Let's represent any point on line L2L_2 using a parameter λ\lambda. The general coordinates of a point on L2L_2 are (2λ+9,−3λ+13,6λ+17)(2\lambda + 9, -3\lambda + 13, 6\lambda + 17). This point will be the intersection point if it also lies on L1L_1.

Step 3: Substitute general point into line L1 equation

For the point on L2L_2 to also lie on L1L_1, its coordinates must satisfy the equation of L1L_1. We substitute the general coordinates of the point from L2L_2 into the equation for L1L_1.

Step 4: Solve for λ\lambda

From the second part of the equation for L1L_1, y−40\frac{y-4}{0}, the numerator must be zero for the expression to be defined (representing a line parallel to the yy -axis in the yy -direction). So, (−3λ+13)−4=0(-3\lambda + 13) - 4 = 0, which simplifies to −3λ+9=0-3\lambda + 9 = 0. Solving for λ\lambda, we get λ=3\lambda = 3. We can verify this with the other parts of the equation.

Step 5: Find the intersection point Q

Now that we have the value of λ\lambda, we can substitute it back into the general coordinates of the point on L2L_2 to find the intersection point QQ. This point QQ is (15,4,35)(15, 4, 35).

Step 6: Calculate the distance PQ

Finally, we calculate the distance between the given point P(7,10,11)P(7{,}10{,}11) and the intersection point Q(15,4,35)Q(15{,}4{,}35) using the distance formula in 3D. The distance is (x2−x1)2+(y2−y1)2+(z2−z1)2\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2 + (z_2-z_1)^2}.

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