Requested by User:Anarchy219 here
Let's get moving
What we can see of the building is 301 pixels tall, while the building is 195 pixels wide, and the hole has a diameter of 81 pixels, radius of 40.5 pixels, discrepancy of 0.64784053156 and 0.13455149501 respectively.
The full view of the building is a bit cut off, so I can't say this is the full height of a high rise... But, it does seem like we see a good majority of it, and since 20 meters is the absolute minimum, I think that's a fair assumption to take in this case. The width by proxy would be 12.9568106312 meters, and the radius of the hole would be 5.44933554791 meters.
This is definitely a cylinder, which is Height (in this case, since it's perpendicular to the building, width) times Pi times Radius^2
So, 12.9568106312 times pi times 5.44933554791^2 is a volume of 1208.74609974 cubic meters. Buildings aren't solid blocks of stone, so, taking off 80% for hollowness leaves 241.749219948 cubic meters, 241749219.948 cubic meters.
The pieces left behind are very small, so times 20 for violent frag of concrete is...
4834984398.95 Joules, 1.15558900549 Tons of TNT, Building level
It's so close to + and they seem only mildly inconvenienced by this, so you could probably say this is worthy of a + rating.