Question

What is the mDEF? plz help

Answer 1

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°