Answer:
No, it is not a right triangle.
Step-by-step explanation:
The simplest way to determine is testing out the numbers with Pythagorian theorem.
If it complies with the theorem, it is a right triangle.
let's assume c = 28, b = 21, and a = 20
the longest side is the hypotenuse so side c (28 in) will be the hypotenuse.
According to the Pythagorian theorem, the square of the length of hypotenuse must equal to the sum of squares of other two sides.
check:
c^2 = 28^2 = 784
a^2 + b^2 = 21^2 + 20^2 = 841
because c^2 is not equal to a^2 + b^2, the triangle is not a right triangle.
Answer:

Step-by-step explanation:
You need 2 things in order to solve this equation: a trig identity sheet and a unit circle.
You will find when you look on your trig identity sheet that

so we will make that replacement, getting everything in terms of sin:

Now we will get everything on one side of the equals sign, set it equal to 0, and solve it:

We can factor out the sin(theta), since it's common in both terms:

Because of the Zero Product Property, either
or

Look at the unit circle and find which values of theta have a sin ratio of 0 in the interval from 0 to 2pi. They are:

The next equation needs to first be solved for sin(theta):
so
and

Go back to your unit circle and find the values of theta where the sin is -1/2 in the interval. They are:

Are you good in geometry I can do this fort you if do my question about geometry ok
Maybe rate of change? Im not sure.