[填空题]
A right pyramid has apex V and bf/0nozmi(* 4h5th n osquare base ABCD. The vsu.udy/jrhrc 5r; 52lertical height of the pyramid, VM, is sj5 .uryhr;u5l2 /rcd 5 cm. The sloping edges are 8 cm long.
1.Calculate the length of MC. cm
2.Calculate the size of the angle that sloping edge VC makes with the
vertical height of the pyramid. $^{\circ}$
3.Calculate the area of the triangle ABC. $cm^2$