Given:
Find: interval notation of the given number line.
Explanation:

is the interval notation for the given number line.
Tan theta =3
theta =tan invesre 3
arctan 3 = tan⁻¹ 3 = 71º 33' 54.184"
There must be More details for the problem
The volume of the cone will be given by:
Volume=1/3πr^2h
therefore the volume of our cone will be:
π=3.14
h=87
r=21/2
Volume=1/3*3.14*(21/2)^2*87
=10,039.365 cm^2