Find the Alpha Angle in Triangle ABC with 89° Interior Angle

Question

Find the measure of the angle $\alpha$

00:00 Find the value of A

00:03 The sum of angles in a triangle equals 180

00:07 We'll substitute appropriate values according to the given data and solve for A

00:12 Group terms

00:16 Isolate A

00:21 And this is the solution to the question

Let's remember that the sum of angles in a triangle is equal to 180 degrees.

Therefore, we will use the following formula:

$A+B+C=180$

Now let's input the known data:

$89+5\frac{1}{2}+\alpha=180$

$\alpha+94.5=180$

We'll move the term to the other side and keep the appropriate sign:

$\alpha=180-94.5$

$\alpha=85.5$

$85\frac{1}{2}$