From the above question

we apply VBODMAS rule,

= (?)²+(65)²=(160)²-(90)²-(7191)

= (?)²=(160)²-(90)²-(7191)-(65)²

= (?)²=25600-8100-7191-4225

= (?)²= 6084

= ? =√6084

= ? = 78

Hence, Option E is correct.