Le Matou matheux : solid shapes

Luxor's Obelisk

This obelisk came from Luxor's temple
and can currently be seen in the centre
of the Concorde square in Paris

In 1831, the obelisk was offered
by the vice-king of Egypt to France,
but it was only erected in 1836
after Champollion's death.

The uppermost piece, called a pyramidion, is a pyramid with a squared base with side 1.66 m and height 3.60m. What is its volume in m³, rounded to the nearest tenth?

Using the following formula, calculate the volume of the central piece in m³, rounded to the nearest unity:

V =	h	(a² + ab + b²)	V =
	3
height of the central piece= h= 22,83 m side of the obelisk's base= a = 2,43 m side of the pyramidion's base = b = 1,66 m

Except for the pyramidion, this obelisk is in pink granite. Calculate the mass of pink granite, in tons, knowing that the volumic mass of pink granite is about 2 500 kg/m³. Round your answer to the nearest unity.

tons

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Luxor's Obelisk