Question text1. The two figures below show the geometry of the Airy and Pratt isostasy hypothesis. a) For the Airy geometry, calculate the thickness of the root “r” in km to two significant figures. You know that: [math: ρm=3g/cm3|ρc=2.1g/cm3|h=2.8km|tc1=10km]r = Answer 1 Question 4[input] km [3] b) For the Pratt geometry, calculate the density of [math: ρc2] in [math: g/cm3] to two significant figures given that: [math: ρc1=2.4g/cm3|h=1km|tc1=7.6km][math: ρc2=] Answer 2 Question 4[input] [math: g/cm3] [3] c) The Figure below shows a crustal block with mean density [math: ρ2=3000kg/m3] that is initially in isostatic equilibrium with the surrounding medium whose mean density is [math: ρ1=3200kg/m3]. After subsequent erosion of the initial block (a), the surface topography looks as shown in figure (b). The distance [math: L=7.7km] remains constant and Airy type isostasy is maintained. Calculate the amount by which the height of point A is changed in m to two significant figures. (Hint: use balance between weight and buoyant force)[math: hfinal−hinitial=] Answer 3 Question 4[input] [math: m] [4]