Final Answer:
1. The value of r is 15.
2. The sine of the angle is 0.8.
3. The cosine of the angle is 0.6.
4. The tangent of the angle is
or approximately 1.33.
5. The angle is 36.87°.
Step-by-step explanation:
To determine r in the Cartesian coordinate system, we use the Pythagorean theorem,
. Given the point (9, 12),
. Calculating this,
, and
Taking the square root of both sides,
Therefore, the value of r is 15.
The sine of an angle in standard position is defined as
. In this case,

The cosine of an angle is defined as
. In this instance,

The tangent of an angle is given by
. For this point,
, which is approximately 1.33.
Finally, to find the angle
, we use the arctangent function:
. Calculating this, we find
. Therefore, the angle is approximately 36.87°.