D=2r=2·4=8 cm
A = L² (L=d)
A = 8² = 64 cm²
<span>a. True
The question is pretty much the entire definition of a radian. For an unit circle, its entire circumference is 2π and the entire circle has 2π radians. A quarter circle, or 90°, or π/2 radians, have 1/4th of the circumference. And 2π/4 is π/2. This natural relationship is WHY higher mathematics uses radians for the measurement of angles rather than arbitrary units such as degrees.</span>
The first one is incorrect. The actual solution of the problem is 5/2. I’m sorry i’m in a rush right now. But that’s all I can answer right now.
Given :
The foci of hyperbola are (8,0) and (-8,0) .
The difference of the focal radii = 6.
To Find :
The equation of the hyperbola.
Solution :
We know, distance between foci is given by :
2c = 8 - (-8)
c = 8
Also, difference between the foci or focal distance is given by :
2a = 6
a = 3
Now, we know for hyperbola :

General equation of hyperbola is :

Hence, this is the required solution.