What is the angle between A330 body and the ground?
TL;DR The angle is about 1 degree.

The best reference I can think of is the aircraft characteristics document provided by Airbus. This provides key dimensions for the A330 family.

I looked at the dimensions for the forward and aft lower deck cargo doors. The document provides both the distance from the ground to the floor of the hold (§2-3-0), and to the door center from the nose (§2-7-0). With this information, an inverse tangent will give the angle of the deck between the doors.

There are two factors that affect these numbers. First, the three models of aircraft have different measurements. The other factor is weight and balance of the aircraft, which affects how much the suspension on each gear is compressed. A heavier aircraft will sit lower to the ground, and the location of the center of gravity will affect how much weight is resting on each landing gear position.

Calculating the angles gives the following angles. Note the larger angle on the shorter -200, and the difference of about a degree between the values on the -200 and the freighter -200F.

Although 1 degree may not seem like much, note the difference of about 33 cm (13 in.) height between the -200 and the -200F at the forward cargo door. This is near the nose gear, which is the reason that modifications were necessary to fit the extra nose gear length in the gear bay.

-300


176,000 kg, CG 26.8%: 1.2 deg
MRW, CG 15%: 1.1 deg
MRW, CG 36.5%: 0.8 deg


-200


119,000 kg, mid CG: 1.4 deg
MRW, CG 21%: 1.3 deg
MRW, CG 37.5%: 0.8 deg


-200F


115,000 kg, CG 20%: 0.4 deg
MRW, CG 20.6%: 0.2 deg
MRW, CG 37.4%: 0 deg