78 rounded to the nearest tenth is 80
Answer:
The third choice, (160/3)π cm³
Step-by-step explanation:
The formula for volume of a cone is
V = (1/3)πr²h where r is the radius of the base, and h is the height
Here, r = 4 and h = 10. plug those values in and simplify...
V = (1/3)π(4²)(10)
V = (1/3)π(16)(10)
V = (1/3)π(160)
V = (160π)/3
Find the area of each shape and add.Let's start with the first semi-circle(half-circle)
If the area of a circle is πr² , then the area of a semi-circle is 1/2πr² where is 22/7 or 3.14, and r is the radius which is 1.8 meters
A=1/2πr²
A=1/2*22/7*1.8*1.8
A=5.09 m²(rounded to nearest hundredth)
Since the semi-circles are two and have the same radius, multiply the area of the first one by two or go through the same process again.
So 5.09 *2=10.18meters square is the area of the two semi-circles
Now, let's find the area of a rectangle which is length times width, where length is 6 meters and width is (1.8+1.8, because 1.8 is half the width)=3.6 meters
A=l*w
A=6*3.6
A=21.6meters square
Therefore the area of the shape is 10.18m²+21.6m²=219.888m²
