# ACT Math 5.4 Coordinate Geometry

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ACT Math: Coordinate Geometry Drill 5, Problem 4. Find the other endpoint.

ACT Math | Coordinate Geometry |

ACT Mathematics | Coordinate Geometry |

Coordinate Geometry | Distance and midpoints Midpoints Section Formula |

Foreign Language | Arabic Subtitled Chinese Subtitled Korean Subtitled Spanish Subtitled |

Language | English Language |

Parallel and Perpendicular Lines | Equations and Slopes of Lines |

Product Type | ACT Math |

### Transcript

...the midpoint between the two points can be found with the formula: x1 plus x2 divided

by 2, y1 plus y2 divided by 2. But we're not given the two endpoints. Instead,

we're given the midpoint and one other point...

Not a problem. Let's place these values in the midpoint formula.

(2,1) equals the quantity 3 plus x... divided by 2... and the quantity negative 4 plus y

divided by 2. So the x coordinate equation is 2 equals 3

plus x divided by 2...and the y coordinate is 1 equals negative 4 plus y divided by 2.

Now let's go to the x coordinate equation. Multiply both sides by 2...

So 4 equals 3 plus x. Then we subtract both sides by 3..

So the x coordinate is 1.

Well, now let's go to the y-coordinate equation.

Multiply both sides by 2. 2 equals negative 4 plus y. Add 4 to both sides...

So y equals 6. And yeah, it's answer choice E!