Atank filled 12 gallons in 2mins, after 5 it contained 30 gallons. what is the constant rate of change?

Hello.

The constant rate of change is 6 gallons. To figure this out, divide the amount of gallons it was filled to, and the minutes. 12 ÷ 2 = 6. It's constant rate would be: 6gal / 1min,   12gal / 2min,   18gal / 3min,    24gal / 4min,    30gal / 5min, etc.

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐