If the values you want to look up are in a SharePoint list, then you need to create a data connection to that list. Make sure to include all the fields you need. Don't load the data connection at form load.
Let the user enter the height. Create a rule for the height field that fires when the field changes. Add an action that sets the query field for the secondary data source to the value of the height field, then query the data connection. Now the secondary data source contains the record with that height and the fields in the secondary data source contain the values. You can copy the values into text boxes on the canvas.
More details: After you have set up a data connection to the Heights list, click the Heights field and add a rule by clicking New > Action.
Click the Add button and add an action to set a field's value.
Click the button next to the "Field" text box. If you don't see the top drop-down to select a different data source than the main data source, click the "Show Advanced View" link. Select the secondary data source for the Heights list, open the node for queryFields and the node below that and select the Height field.
Click the fx button next to the "Value" text box, then click "Insert Field or Group" and select the "height" field of the main data source.
OK out of all dialogs.
Add another rule to query for data.
Select the secondary data source to the Heights list.
Add another rule to set a field's value. For "Field" select the main data source field into which you want to copy the looked up value. For "Value" select the secondary data source and drill into the dataFields node until you see the field names. Select the desired field and OK out of all dialogs.
The rules panel should now look similar to this, but with your column names.
Test the form. Enter a valid height into the height field and click out of the field. The corresponding value from the height list will be written into the textbox. The screenshot shows the SharePoint list in the background with the item for heigt "66" highlighted. The value returned to the InfoPath text box "getV1" is from the "V1" field of the SharePoint list.
Hope that makes it clearer.