Q:

How do I draw a heart shape in inkscape?

I'd prefer the method to draw it using two circles and a rectangle because I think that's the simplest method. But other methods are also OK. I need a not too curvy heart. Something like this.

I tried putting two circles together and a square below them. But I'm not getting a perfect heart. The intersection points of the square and circles are edgy.
I want to know how much distance there should be between the circles and how big the square should be when compared to the circles. Here is my effort's result.

A:

Create a square.

Create a semicircle with the same diameter:

Create a circle.

Move the round control in the circle tool to make it a semicircle, with the straight side being perfectly horizontal and facing downwards.

Select your square, copy, select your semicircle, edit → paste size → paste width. Be sure to have the proportion lock activated (the little lock in the toolbar).

Open the Align and distribute tab, choose relative to as first selected.

Select your square and then your semicircle.
align bottom edge of objects to top edge of anchor.
align left edges.

Duplicate the semicircle and rotate by 90 ° clockwise, repeat step 3 analogously.

Select all three objects, path → object to path and path → union.
Object  → transform → rotate by 45 ̌°.

A:

One more method a bit similar to what Wrzlprmft posted is as follows:

Draw a square (hold Shift+Ctrl while dragging rectangle tool) of 100 units and a semicircle (hold Shift+Ctrl using ellipse tool) of 100 unit width.
Using Align tool place the semicircle on one end of the square. Similarly duplicate the semicircle and place it on the adjacent side of the square as shown.

Group the three objects.
Use object- transform tool- rotate by 45 deg for rotating the grouped object. Ungroup it .
Duplicate the square. With the object being selected click on the rectangle tool. Using the circular node round the edges.

Selecting the two squares use path-division, combine all the parts using path- union, except the bottom rounded corner as shown. 
use path-union to combine the square & semi circle.

A:

I would go about it as follows (more of a visual then a geometrical approach):
1) using the bézier tool, draw a triangular shape as shown below with the left line perfectly vertical (use Ctrl while drawing)

2) Menu Edit > Clone > Create Clone, then with selection tool enabled, flip the clone horizontally (using the icon in the tool options above) and move it to the left, snapping it to the original

3) select the original, and with the node tool tweak the form. You probably want the right node to be smooth.

4) Change fill and stroke as needed. Optional: When you're happy with the result, select the clone, and do Edit > Clone > Unlink Clone. Then select both shapes and do Path > Union. This will give you one path for the final heart shape.

