Big Ideas Math Integrated I, 2016
BI
Big Ideas Math Integrated I, 2016 View details
1-4. Quiz
Continue to next subchapter

Exercise 14 Page 616

What can you say about the sides of an equiangular triangle?

x=5
y^(∘)=20^(∘)

Practice makes perfect

Examining the diagram, we can spot two equiangular triangles which means all angles in these triangles have a measure of 60^(∘). Also, according to the Corollary to the Converse of the Base Angles Theorem, if a triangle is equiangular, then it is equilateral as well. Let's add this information to the diagram.

Therefore, the sides marked as 5x-1 and 24 are congruent. This means we can equate their measures and solve for x.
5x-1=24
5x=25
x=5
To solve for y, we have to consider the fact that 60^(∘) and 6y form a linear pair. By the Linear Pair Postulate we know these angles are supplementary. Therefore, we can equate their sum with 180^(∘) and solve for y.
6y^(∘)+60^(∘)=180^(∘)
6y^(∘)=120^(∘)
y^(∘)=20^(∘)