Given, dimension of the frustum are : radius of one circular part, r1=42cm radius of another circular part, r2=105cm Vertical height, h=16cm In △ABC, (AC)2=AB2+BC2⇒I2=h2+(r2−r1)2 I2=(16)2+(105−42)2
=256+(63)2=256+3969=4225 I=√4225=65cm Hence, the slant height is 65cm.