# ACT Math 1.1 Trigonometry

ACT Math: Trigonometry Drill 1, Problem 1. What is the length of y?

ACT Math | Trigonometry |

ACT Mathematics | Trigonometry |

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

Language | English Language |

Product Type | ACT Math |

Trigonometry | SOHCAHTOA (values and properties of trig functions) Solving right triangles Trigonometric relations in right triangles |

### Transcript

Since we're told that x equals 10, we can set up a ratio that looks like this. And we

cross multiply to solve for z.

We get 10 times 5 equals 50...and 3 times z as 3z. So now divide both sides

by 3 and we get that z equals around 16.7. And now that we have two side lengths of a

right triangle, we can use the Pythagorean Theorem to solve for y.

So now we can just plug in our values.

10 squared plus y squared equals 16.7 squared. 100 plus y squared equals 278.89. Subtract

100 from both sides, and we get that y squared equals 178.89.

Take the square root of both sides, and we get that y equals plus or minus 13.3.

Sides can't be negative...

...so the answer is 13.3. So it's A.