Find out what half of 39° (angle ABD) Then subtract that from 180° (angle ABE). When the plain flus faster angle (ABD) gets smaller and angle (ABE) gets bigger. Hope that helps.
Answer:
answer number 4 I believe
SA=2pir^2+2hpir=2pir(r+h)
h=2r=2(2x+3)=4x+6
SA=2pi(2x+3)(2x+3+4x+6)
SA=(4x+6)(pi)(6x+9)
SA=24πx²+27πx+54π
Use photo math , I’m sure it will help