A $200$ km long $345-kV$ transmission line serving a $0\mathrm{.}9$ lagging power factor load has its sending$-$end voltage at $1\mathrm{.}25$ pu and receiving$-$end voltage at $1$ pu $.$ According to the nose curves' diagram in Fig. $10\mathrm{.}4($b$)$ of the textbook $($reproduced below$),$

a$.$ how much real power $($as a multiple of this line's SIL$)$ is being drawn by this load $?$

b$.$ what's the threshold of real power $($as a multiple of this line's SIL$)$ that will, if drawn by this load at the same power factor, cause the line's voltage to collapse?