Answer: the height of the Washington monument is 555 feet.
Step-by-step explanation:
Let x represent the height of the Washington monument.
The empire State building is 1250 feet tall this is 140 feet more than twice the height of the Washington monument. This would be expressed as
1250 = 2x + 140
Subtracting 140 from the left hand side and the right hand side of the equation, it becomes
1250 - 140 = 2x + 140 - 140
2x = 1110
Dividing the left hand side and the right hand side of the equation by 2, it becomes
2x/2 = 1110/2
x = 555 feet
