Answer:
m∠DEF = 148°
Step-by-step explanation:
The total sum of angles inside a triangle is 180°
m∠FDE + m∠EFD + m∠DEF = 180°
We can also see that because two sides are congruent, their angles are also congruent, so we can solve for x
m∠FDE = m∠EFD
2x + 8 = 3x + 4; subtract 2x from both sides
8 = x + 4; subtract 4 from both sides
x = 4; now we can substitute into equations
m∠FDE = m∠EFD;
2(4) + 8 = 3(4) + 4
8 + 8 = 12 + 4; 16=16; therefore = m∠FDE = m∠EFD = 16
To solve for m∠DEF
m∠FDE + m∠EFD + m∠DEF = 180°
16 + 16 + m∠DEF = 180
m∠DEF = 148°
