Find the value of x. Round the length to the nearest tenth

What is the missing constant term in the perfect square that starts with x^2 -20x

1. ∠1 is complementary to ∠2 and ∠3 is complementary to ∠2. subtraction property of equality 2. m∠1 + m∠2 = 90 and m∠3 + m∠2 = 90 substitution 3. m∠1 + m∠2 = m∠3 + m∠2 definition of complementary 4. m∠1 = m∠3 given

Sara has 2 2/3 cup taco meat. she needs 1/6 cup to make one taco. how many tacos can sara make with the taco meat she has?