2 círculos (con lie factor = 1) by aaizemberg

index.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.3/d3.min.js"></script>
  <title>lie factor</title>
</head>
<body>

<script>
var radio = d3.scaleLinear()
              .domain([0, 100])
              .range([0, 50]);

  var area = d3.scaleSqrt()
               .domain([0, 100])
               .range([0, 50]);

var ex = d3.scaleLinear()
           .domain([0, 1])
           .range([50, 150]);

var svg = d3.select("body")
  .append("svg")
  .attr("width",200)
  .attr("height",200);

var data = [50,100];

svg.selectAll("circle").data(data).enter().append("circle")
   .attr("cx", (d,i) => ex(i) )
   .attr("cy",100)
   .style("stroke","black")
   .style("fill","none")
   .attr("r", (d) => area(d) );
</script>  
  
</body>
</html>