Answer:
5cm = r
Step-by-step explanation:
The area of a circle is given by
A = pi r^2
78.5 = 3.14 r^2
Divide each side by 3.14
78.5/ 3.14 = r^2
25 = r^2
Take the square root of each side
sqrt(25) = sqrt(r^2)
5 = r
Answer:
C) 100 m^2
Step-by-step explanation:
Area of a trapezoid= h*[(b1+b2)/2]
h=10
b1=8
b2=12
Therefore:
A=10*[(8+12)/2]
A=10*(20/2)
A=10*10
A=100
So the area of the trapezoid is 100 m^2
Answer:
a. 1 1/8 b. 8/9
Step-by-step explanation:
You can set this up as a proportion to solve. For part a. we know that 2/3 of the road is 3/4 mile long. 2/3 + 1/3 = the whole road, so we need how many miles of the road is 1/3 its length. Set up the proportion like this:

Cross multiplying gives you:

The 3's on the right cancel out nicely, leaving you with

To solve for x, multiply both sides by 3/2:
gives you

That means that the road is still missing 3/8 of a mile til it's finished. The length of the road is found by adding the 3/4 to the 3/8:

So the road is a total of 1 1/8 miles long.
For b. we need to find out how much of 1 1/8 is 1 mile:
1 mile = x * 9/8 and
x = 8/9. When 1 mile of the road is completed, that is 8/9 of the total length of the road completed.