Answer:
15 degrees
Step-by-step explanation:
Draw a horizontal segment approximately 4 inches long. Label the right endpoint A and the left endpoint C. Label the length of AC 4.2 meters. That is the horizontal distance between the eye and the blackboard.
At the right endpoint, A, draw a vertical segment going up, approximately 1 inch tall. Label the upper point E, for eye. Label segment EA 1 meter since the eye is 1 meter above ground.
At the left endpoint of the horizontal segment, point C, draw a vertical segment going up approximately 2 inches. Label the upper point B for blackboard. Connect points E and B. Draw one more segment. From point E, draw a horizontal segment to the left until it intersects the vertical segment BC. Label the point of intersection D.
The angle of elevation you want is angle BED.
The length of segment BC is 2.1 meters. The length of segment CD is 1 meter. That means that the length of segment BD is 1.1 meters.
To find the measure of angle BED, we can use the opposite leg and the adjacent leg and the inverse tangent function.
BD = 1.1 m
DE = 4.2 m
tan <BED = opp/adj
tan <BED = 1.1/4.2
m<BED = tan^-1 (1.1/4.2)
m<BED = 15
Answer: 15 degrees
Answer:
D
Step-by-step explanation:
sin A = opp. /hyp. = CB/AB = 12/ 15 so CB =12 and AB=15
apply Pythagorean Th. for triangle ABC to find AC
AC²= AB²-CB² = 15²-12² = 81; AC = √81=9
tan A = opp./adj. = CB /AC = 12/ 9 = 4/3
Answer:
(5,-2)
Step-by-step explanation:
9x+5y=35
2x+5y=0
Multiply the second equation by -1
-1 (2x+5y) = 0*-1
-2x-5y = 0
Add the first equation and the modified second equation
9x+5y=35
-2x-5y = 0
-------------------
7x = 35
Divide by 7
7x/7 = 35/7
x = 5
Now we need to find y
2x+5y = 0
Substituting in x
2(5) +5y = 0
10 +5y = 0
Subtract 10
10-10 +5y = -10
5y = -10
Divide by 5
5y/5 = -10/5
y = -2
(5,-2)
Use distance = rate x time
18 minutes is 3/10 of an hour.
So the distance to the store is:
d = 20*(3/10) = 6 miles
The distance downhill is the same, 6 miles. So:
6 = (60)t
6/60 = t
1/10 = t
Where t is the time it took to go back home. So t is .1 hour (6 minutes).
To calculate average speed we use the formula:
average speed = total distance/ total time
average speed = (6+6)/(.3 + .1) = 12/(.4) = 30
So her average speed for the entire trip is 30 mph (miles per hour).
Answer:
5
Step-by-step explanation: