Answer:
7 feet
Explanation:
Oak tree = x
14 : x as 60 : 30
Simplify the right ratio
14 : x as 2:1
Get the same first number in both ratios by multiplying 2:1 by 7
14 : x as 2(7) + 1(7)
14 : x as 14 : 7
Since the first number in each ratio is the same, we know that that x and 7 are equal
x = 7
Hope this helps, feel free to let me know if you would like a further explanation :)