Answer:
98 units
Step-by-step explanation:
Diagonal=√side1²+side2²−2⋅side1⋅side2⋅cos(corresponding angle - a)
70² = 40²+75²-2*40*75⋅cos(a)
cos(a) = (40²+75²-70²) / 2*40*75
cos(180°-a) = -cos(a)
Other diagonal² = 40²+75²-2*40*75* (-(40²+75²-70²) / 2*40*75)
Other diagonal = 97.72
