9514 1404 393
Answer:
78.71 mph
Step-by-step explanation:
You're looking for the solution to ...
d = 88
0.0015r^2 +r = 88
0.0015r^2 +r -88 = 0
Using the quadratic formula*, we find ...
r = (-1 +√(1² -4(0.0015)(-88)))/(2×0.0015)
r = (-1 +√1.528)/0.003 = 0.236123/0.003 = 78.7077
The speed of the car was about 78.71 mph.
_____
* The quadratic formula will also give a negative answer of about -745 mph, which is not relevant to the situation.
Answer:
m∠ABC = 119° and DC = 105 feet
Step-by-step explanation:
For better understanding of the solution see the attached figure of the trapezium ABCD :
m∠BCD = 61°
By using the property, Sum of interior opposite angles in a trapezium is supplementary ⇒ m∠BCD + m∠ABC = 180°
⇒ m∠ABC = 180° - 61°
⇒ m∠ABC = 119°
Now, to find length of DC,
Draw a perpendicular BE on CD ⇒ CD = DE + EC
AB = DE
⇒ DE = 80 feet
In ΔBEC, By using Pythagoras theorem
EC² = BC² - BE²
⇒ EC² = 65² - 60²
⇒ EC = 25 feet
Hence, DC = 80 + 25
= 105 feet
