<Tr> <Th> Height </Th> <Td> 146.7 metres (481 ft) or 280 Egyptian Royal cubits 138.8 metres (455 ft) (contemporary) </Td> </Tr> <Tr> <Th> Base </Th> <Td> 230.34 metres (756 ft) or 440 Egyptian Royal cubits </Td> </Tr> <Tr> <Th> Volume </Th> <Td> 2,583,283 cubic metres (91,227,778 cu ft) </Td> </Tr> <Tr> <Th> Slope </Th> <Td> <P> 51 ° 52' ± 2' </P> </Td> </Tr>

When were the pyramids of giza first discovered