Answer:
B. DE = 58
Explanation:
The base angles (<F and <E) of the ∆DEF are congruent/equal. This means that ∆DEF is an isosceles triangle.
This implies that, the two sides (DF and DE) that are opposite to the base angles are congruent/equal.
DE = 40 (given) => option B is INCORRECT
Therefore:
8x - 24 = 40
Solve for x
8x - 24 + 24 = 40 + 24
8x = 64
8x/8 = 64/8
x = 8 (option C is CORRECT)
Let's find DF and FE:
DF = 8x - 24
Plug in the value of x
DF = 8(8) - 24
DF = 64 - 24
DF = 40 (Option D is CORRECT)
FE = 6x + 10
FE = 6(8) + 10
FE = 48 + 10
FE = 58 (Option A is CORRECT)
The only incorrect statement is:
B. DE = 58