SVG Half Circle: Why is it rotated?

I am experimenting with SVG elements. I am trying to create a simple half circle but my half circle is rotated for some reason? How can I get the half circle to not rotate?

My methodology is:

• The SVG 'canvas' is 400 by 400px, th0e half circle will have a radius of 180px
• MoveTo point: 20,200 - M20,200
• LineTo: draw a line 360px long & does not change the y position - L360,0
• ArcTo: draw an arc to complete the circle, the radius of the arc is 180px - A180,180 0 0,1 20,200

In code this is:

<svg width="400" height="400">
    <path d="M20,200 L360,0 A180,180 0 0,1 20,200 z"
        style="fill:#ff0000;
            fill-opacity: 1;
            stroke:black;
            stroke-width: 1"/>
</svg>

PS: If I want to create a pie chart that is only 275degrees, would the best way be to make 2 paths, one 180degrees(the half circle above) & another path of 90 degrees? Or is it possible to create this with 1 Path? Is so would anyone be kind enough to show an example SVG code?