Find all the angles of the isosceles triangle below:
We have hundreds of course questions with personalized recommendations + Account 100% premium
Find all the angles of the isosceles triangle below:
Let's remember that in an isosceles triangle, the base angles are equal to each other.
In other words:
We know the vertex angle, which is equal to 70 degrees, and we know that the sum of angles in a triangle is equal to 180 degrees.
Therefore, we can calculate the base angles in the following way:
Therefore, the angle values in the triangle are 55, 55, and 70.
70, 55, 55
Find the measure of the angle \( \alpha \)
The base angles are the two angles opposite the equal sides. In this triangle, angles B and C are at the base, while angle A (70°) is the vertex angle at the top.
In an isosceles triangle, the two equal sides create identical triangular shapes on each side. This symmetry means the base angles must be exactly the same size!
That's the total for both base angles combined! Remember to divide by 2: for each base angle.
Yes! This method works whenever you know the vertex angle: subtract it from 180°, then divide by 2. The base angles are always equal in isosceles triangles.
Add all three angles together: they must equal 180°. Also verify that the two base angles are equal to each other: 55° = 55° ✓
Get unlimited access to all 18 Angles questions, detailed video solutions, and personalized progress tracking.
Unlimited Video Solutions
Step-by-step explanations for every problem
Progress Analytics
Track your mastery across all topics
Ad-Free Learning
Focus on math without distractions
No credit card required • Cancel anytime