How long is a foot? please write a full answer.

Describe the 2 algebraic methods you can use to find the zeros of the function f(t)=-16t^2+400.

Need 50 will mark brainliest answer. find the lengths of all the sides and the measures of the angles.

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.