[填空题]
A right pyramid has a .fr9b q9/7yow+sgj dd5,xvw.2j ul pjf*e* kem1r69jv 7eypcpex V and square base ABCD. The vertical height of the pyramid upkjv71l , rmcje62.9xfype*ejvw 5*, VM, is 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. $cm^2$