Answer:
63
Step-by-step explanation:
a=9
7a
7(9)
63
To calculate the sine of an angle, simply divide the length of the opposite side, 479.16, by the length of the hypotenuse, 610. To get the cosine, divide the length of the adjacent side, 377.5, by the length of the hypotenuse, 610.
Answer:

Step-by-step explanation:

We can try to simplify first.

Now we can combine the like terms:

hope this helped! :)
Not A because regular means all sides are equal.
B has to be the answer because the others are not.
Not C because a right triangle is not regular, i.e. and equilateral triangle.
Not D because a rectangle has different side lengths.