Word | know | Unknown
Language| 12 | x
Total | 180 | 28980
Use cross multiply:
12(28980) = 180(x)
347760 = 180x
347760/180=1932
Z=82 vertical or opposite angle theorem
15x-7 + 82=180 supplementary angles theorem
so 15x +75 =180
15x=180-75
x=105/15
x=7
Volume of a pyramid = 
Given base is = 140 m
Given height is = 96 m
Volume = 
Hence, volume of pyramid is 4480 m³