Answer:
DE = 2.5 feet
Explanation:
The Two-Tangent Theorem say that if two tangents (DE and FE in our case) to the same circle ( circle G in our case) are drawn from the same external point (point E in our case) then they are congruent.
If DE ≅ FE then their measures are equal 3x -3.5 = x +0.5
Solve for x
3x -3.5 = x+0.5, add 3.5 and subtract x from both sides
3x -x = 3.5 +0.5, combine like terms
2x = 4 , divide both sides by 2
x =2
Substitute x = 2 into DE = 3x -3.5
DE = 3*2 -3.5 = 6 -3.5 = 2.5