I need help with this plz

Iwill give ! if m∠a=59 and m∠3=81°, what is m∠b? m∠b= _[blank]_°

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g

Which is greater or equal 312 mg or 312 dg