Create a pie chart

Mathematica, 186 183 164 bytes

Graphics[{Hue@#,Disk[{0,0},{1,1},a=2Pi{##}],Black,Text[ToString@Round[100(#2-#)]<>"%",5Through@{Cos,Sin}@Mean@a/4]}&@@@Partition[Accumulate[#/Tr@#]~Prepend~0,2,1]]&

Could be golfed further. Currently generates a Graphics object. Test cases:

JavaScript (ES6), 311 310 302 298 bytes

a=>{with(Math)document.write(`<svg height=300>`+a.map(n=>`<path fill=#${(p*4e3|0).toString(16)} d=M135,150L${c(o=100,v=0)}A${[o,o,0,(v=n/=s)+.5|0,0,c(o)]}Z /><text x=${(z=c(135,v/=2))[0]} y=${z[p+=n,1]}>${n*o+.5|0}%</text>`,c=r=>[sin(d=PI*2*(v+p))*r+135,cos(d)*r+150],p=s=0,a.map(n=>s+=n)).join``)}

Saved a byte with help from @Neil!

Explanation

Writes some SVG to the HTML of the current page. Builds the chart with centre point 135 x 150 of radius 100px and text at a radius of 135px from the centre.

var solution =

a=>{
  with(Math)
  document.write(       // write to HTML body
    `<svg height=300>`+ // create 300px x 300px SVG canvas (width defaults to 300px)
    a.map(n=>           // for each number
      
      // Get the hex colour by multiplying the current position by (roughly) 0xfff
      `<path fill=#${(p*4e3|0).toString(16)
      
      // Calculate the path of the pie slice
      } d=M135,150L${c(o=100,v=0)}A${[o,o,0,(v=n/=s)+.5|0,0,c(o)]
      
      // Text
      }Z /><text x=${(z=c(135,v/=2))[0]} y=${z[p+=n,1]}>${n*o+.5|0}%</text>`,
      
      // Returns [ x, y ] for a certain radius at position v around the pie
      c=r=>[sin(d=PI*2*(v+p))*r+135,cos(d)*r+150],
      p=s=0,             // p = current position around pie (0 - 1)
      a.map(n=>s+=n)     // s = sum of all numbers
    ).join``
    
    +`</svg>` // <- this is just here for the test, so multiple charts can be displayed
  )
}

// Test
;[
  [0.3, 1.2],
  [3, 6, 2, 10],
  [0.4387, 0.3816, 0.7655, 0.7952, 0.1869, 0.4898, 0.4456, 0.6463, 0.7094, 0.7547]
].map(c=>solution(c));

Python + PIL, 365 355

from math import*;from random import*
from PIL import Image,ImageDraw
L,a,r=256,0,0.8;l,p,c=L/2,L/6,(L,L,L);I=Image.new('RGB',(L,L),c);D=ImageDraw.Draw(I)
x=input()
for i in x:b=a+ceil(360.0*i/sum(x));D.pieslice((p,p,L-p,L-p),int(a),int(b),tuple(map(randrange,c)));t=(a+b)*0.00872;D.text((l+cos(t)*l*r,l+sin(t)*l*r),str(int((b-a)/3.6))+'%',0);a=b
I.show()

Result for the largest example list :