Answer:
87.9°
Step-by-step explanation:
arctan(50/40)=87.9°
Divide 3 1/2 by 7= 1/2 a cup per person
No because it would be
if you knew that
ax^2+bx+c was a trinomial square, then the factored form would be

or

so
if w^2-9w+81 is perfect square, factored form is either

or

aka

or
expand them
(x+9)^2=x^2+18x+81, wron middle term
(x-9)^2=x^2-18x+81 wrong
so it is not
Diameter of the circle is BD as shown, as indicated and passed through center where BD passes, triangle ABD is a right triangle with angle ABD as the right angle. It means ADB and ABD are complementary which means
AB = 140 degree
AD=40 degree