How to Draw a Circle Sector in Css

.pie {
  overflow:hidden;
  position: relative;
  margin: 1em auto;
  border: dashed 1px;
  padding: 0;
  width: 32em; height: 32em;
  border-radius: 50%;
  list-style: none;
}
.slice {
  overflow: hidden;
  position: absolute;
  top: 0; right: 0;
  width: 50%; height: 50%;
  transform-origin: 0% 100%; 
}
.slice:first-child {
  transform: rotate(15deg) skewY(-22.5deg);
}
.slice-contents {
  position: absolute;
  left: -100%;
  width: 200%; height: 200%;
  border-radius: 50%;
  background: lightblue;
}
.slice:first-child .slice-contents {
  transform: skewY(22.5deg); /* unskew slice contents */
}
.slice:hover .slice-contents { background: violet; } /* highlight on hover */

<ul class='pie'>
  <li class='slice'>
    <div class='slice-contents'></div>
  </li>
  <!-- you can add more slices here -->
</ul>

Drawing a circle (with sectors) using HTML, CSS, or jQuery

How about Raphael.js?

From the web site:

Raphaël is a small JavaScript library
that should simplify your work with
vector graphics on the web. If you
want to create your own specific chart
or image crop and rotate widget, for
example, you can achieve it simply and
easily with this library.

...

Raphaël currently supports Firefox
3.0+, Safari 3.0+, Chrome 5.0+, Opera 9.5+ and Internet Explorer 6.0+.

How to create a circle with links on border side

The key to creating a circle with segments is to find points along the circle which would be used in the SVG path elements as coordinates. Finding points on a circle can be done easily using trigonometric equations if we know the angles.

X Coordinate of point = Radius of the circle * Cos(Angle in Radians) + X Coordinate of center point

Y Coordinate of point = Radius of the circle * Sin(Angle in Radians) + Y Coordinate of center point

Angle in Radians = Angle in Degrees * Math.PI / 180

The angles depend on the no. of segments that we have to create. The generic formula is (360 / no. of segments). So to create a circle with 6 segments, the angle covered by each of the segment would be 60 degrees. The first segment would cover from 0 to 60 degrees, second from 60 to 120 degrees and so on.

Demo of Circle with 6 Segments:

Below table shows how the points are calculated for a circle with 6 segments (where radius of circle is 50, center point is 55,55):

Once the points are calculated, coding the path itself is simple. The path should start and end at the center point (which is 50,50), from the center point, we should first draw a line to From Point and from there draw an arc to the To Point. Below is how a sample path would look like:

<path d='M55,55 L105,55 A50,50 0 0,1 80,98.30z' />

svg {
  height: 220px;
  width: 220px;
}
path {
  fill: transparent;
  stroke: black;
}

<svg viewBox='0 0 110 110'>
  <path d='M55,55 L105,55 A50,50 0 0,1 80,98.30z' />
  <path d='M55,55 L80,98.30 A50,50 0 0,1 30,98.30z' />
  <path d='M55,55 L30,98.30 A50,50 0 0,1 5,55z' />
  <path d='M55,55 L5,55 A50,50 0 0,1 30,11.69z' />
  <path d='M55,55 L30,11.69 A50,50 0 0,1 80,11.69z' />
  <path d='M55,55 L80,11.69 A50,50 0 0,1 105,55z' />
</svg>

#cone { 
  width: 0;
  height: 0;
  border-left: 70px solid transparent;
  border-right: 70px solid transparent;
  border-top: 100px solid red;
  -moz-border-radius: 50%;
  -webkit-border-radius: 50%;
  border-radius: 50%;

context.moveTo(cx,cy);
context.arc(cx,cy,radius,startangle,endangle);
context.lineTo(cx,cy);
context.stroke(); // or context.fill()