# Distance From a Point to a Plane in 3D-Space

**Problem**

Find the distance from the point *A*(1, 5, -3) to the plane 4*x* + *y* + 8*z* + 33 = 0.

A. 1/2 | C. 2/3 |

B. 2 | D. 1.5 |

**Answer Key**

[ B ]

**Solution**

$d = \left| \dfrac{ax_1 + by_1 + cz_1 + d}{\sqrt{a^2 + b^2 + c^2}} \right|$

$d = \left| \dfrac{4(1) + 1(5) + 8(-3) + 33}{\sqrt{4^2 + 1^2 + 8^2}} \right|$

$d = 2 ~ \text{units}$ ← Answer: [ B ]

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