Use Pythagorean theorem
a² + b² = c²
30² + b² = 78²
b² = 5184
b = √5184
b = 72
Answer:
I think its 72
Step-by-step explanation:
Im not 100% but i think you have to add every side and you have to comlite 180 so 180-78-30=72.....
Im sure that this is what you do with the corners but it could be the same for the sides maybe
