Also answer the hint question and explain your steps please! Three uniform glass slabs $1,2,3$ are being stacked for making solar panels

as shown below. Each slab has a weight $W$ and length a and a rectangular cross

section as shown. Find the maximum distance $d$ that the top slab $1$ can extend out

from slab $2$ so that the stack consisting of slabs $1$ and $2$ does not topple over out of

slab $3.$ The final answer must express $d$ in terms of $a.$

Hint: Under what condition will slab $1$ topple? And what is the condition for the top

two slabs $($slab $1+$ slab $2$ together$)$ to topple?