Which equation can be used to find the unknown length, a, in this triangle?

Using the Pythagorean Theorem a^2 + b^2 = C^2

a and b are the sides and C is the Hypotenuse.

The picture you have sides of a and 15 and the hypotenuse is 17

The formula becomes a^2 + 15^2 = 17^2

For this case, what we must do is find an equation where we can clear the value of a.

We observe that the triangle has an angle of 90 degrees.

We then have to use the Pythagorean theorem to solve the problem.

We have then:

From here, we can clear the value of a.

An equation that can be used to find the unknown length, a, in this triangle is:

it's both, now can you answer my most recent question?

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.