I need help ASAP! (It’s about interior angles)

Step-by-step explanation:

Use distance formula to find the lengths of the sides.

a = √((8 − (-7))² + (-6 − (-4))²) = √229

b = √((8 − (-8))² + (-6 − (-5))²) = √257

c = √((-7 − (-8))² + (-4 − (-5))²) = √2

Use law of cosine to find one of the angles.

c² = a² + b² − 2ab cos C

(√2)² = (√229)² + (√257)² − 2(√229)(√257) cos C

2 = 229 + 257 − 2√58853 cos C

cos C = 242/√58853

C = 4.018°

To find the second angle, either use law of sines, or use law of cosine again.  Using law of cosine:

b² = a² + c² − 2ac cos B

(√257)² = (√229)² + (√2)² − 2(√229)(√2) cos B

257 = 229 + 2 − 2√458 cos B

cos B = -13/√458

B = 127.405°

Finally, find the third angle using sum of angles of a triangle, or law of sines, or law of cosine.  Using law of cosine:

a² = b² + c² − 2bc cos A

(√229)² = (√257)² + (√2)² − 2(√257)(√2) cos A

229 = 257 + 2 − 2√514 cos A

cos A = 15/√514

A = 48.576°

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.