Answer:
41.68 or 42 (rounded)
Step-by-step explanation:
Presuming you are working on right triangles, you can use the Soh Cah Toa theorems.
Because angle A = 21 and side a = 16 you can use Toa or 

Plugged into a calculator, you get 41.68 and some change.
If this is NOT a right triangle question, please let me know so that I can revise my answer.
Answer:
56
Step-by-step explanation:
Answer:
r + ¾ = ⁷/₈
r = ⁷/₈ - ¾
⁷/₈ - ⁶₈ = ¹/₈
r = ¹/₈
Step-by-step explanation:
but my original answer was 4/4
3x^2-5x-24=0
3x^2-5x=24
x^2-5x/3=8
x^2-5x/3+25/36=8+25/36
(x-5/6)^2=313/36
x-5/6=±√(313/36)
x=5/6±√(313/36)
x=(5±√313)/6
p=(5+√313)/6
q=(5-√313)/6
Check the picture below.
keeping in mind that a circle has a total of 360°, if the twin angles of 72° add up to 144°, what remains for the other twin angles is 360° - 144° = 216°, and that 216 is split between both twins for 108 a piece, taking away the 40° next to ∡2, gives us ∡2.