9514 1404 393
Answer:
3.61 seconds
Step-by-step explanation:
The bird starts 50 feet in the air, so will come down to a height of 40 feet after 3.61 seconds.
We want to solve h = 40.
40 = -16t^2 +55t +50
16t^2 -55t -10 = 0
t = (55 +√(55^2 -4(16)(-10)))/(2(16)) = (55 + √3665)/32 ≈ 3.61060
The bird will be 40 ft above the ground the first time after about 3.61 seconds.
*see attachment for the missing figure
Answer:
Angle ADE = 45°
Angle DAE = 30°
Angle DEA = 105°
Step-by-step explanation:
Since lines AD and BC are parallel, therefore:
Given that angle Angle CBE = 45°,
Angle ADE = Angle CBE (alternate interior angles are congruent)
Angle ADE = 45° (Substitution)
Angle DAE = Angle ACB (Alternate Interior Angles are congruent)
Angle ACB = 180 - 150 (angles on a straight line theorem)
Angle ACB = 30°
Since angle DAE = angle ACB, therefore:
Angle DAE = 30°
Angle DEA = 180 - (angle ADE + angle DAE) (Sum of angles in a triangle)
Angle DEA = 180 - (45 + 30) (Substitution)
Angle DEA = 180 - 75
Angle DEA = 105°
