Answer:
The length of the river on a map is 
Step-by-step explanation:
we know that
The scale of the map is 
That means
1 cm on a map is 5,000,000 cm on the actual
or
1 cm on a map is 50 km cm on the actual
so
using proportion
Answer:
- rate of the boat in still water = 6.5 miles / hour
- rate of the current = 2.5 miles / hour.
Explanation:
<u>1) Name the two variables:</u>
- b: rate of the boat in still water:
With that, the net rates of the boat down the river and upstrean are:
<u>2) Now set the equations for the distance as a function of the times and the rates:</u>
- downstream: 18 miles = (b + c) × 2 hours
- upstream: 18 miles = (b - c) × 4.5 hours
<u>3) Set the system of equations:</u>
- 18 = 2(b + c) ⇒ 9 = b + c . . . Equation (1)
- 18 = 4.5 (b - c) ⇒ 4 = b - c . . . Equation (2)
<u>4) Solve the system by </u><u>elimination</u><u>:</u>
- Add equations (1) and (2): 9 + 4 = 2b
- Divide both sides by 2: 13/2 = b
- Replace b with 6.5 in equation (2) and solve:
4 = 6.5 - c ⇒ c = 6.5 - 4 = 2.5
<u>5) Results:</u>
- b = rate of the boat in still water = 6.5 miles / hour
- c = rate of the current = 2.5 miles / hour.
Answer:
74.4 ,81.5 , median
Step-by-step explanation:
ed20 answers
Let's find the area of the base.
It's a rectangle that's 3.8 by 4.8, so let's multiply.
3.8×4.8=18.24
We have two different triangles.
Triangle one has a height of 2.6 and base of 4.8. But there are two of them.
2.6×4.8×0.5=6.24×2= 12.48; this is the area of two triangles.
Another set of triangles has a height of 2.9 and a base of 3.8.
2.9×3.8×0.5=5.51×2=11.02
Let's add all the areas together.
18.24+12.48+11.02
41.74
The surface area is 41.74 m², so the third option.
