<h2>
Answer:</h2>
The area of the top surface of the washer is: 160.14 square mm.
<h2>
Step-by-step explanation:</h2>
The top of the surface is in the shape of a annulus with a outer radius of 10 mm and a inner radius of 7 mm ( since the diameter of the hole is: 14 mm and we know that the radius is half of the diameter)
Now, we know that the area of the annulus region is given by:

where R is the outer radius and r is the inner radius.
Here we have:

Hence, we have:

Answer:
48 students in the class
Step-by-step explanation:
The ratio of girls to boys is 3 : 5 = 3x : 5x ( x is a multiplier ) , then
5x = 3x + 12 ( 12 more boys than girls )
Subtract 3x from both sides )
2x = 12 ( divide both sides by 2 )
x = 6
Then
number of girls = 3x = 3 × 6 = 18
number of boys = 5x = 5 × 6 = 30
total students in class = 18 + 30 = 48
Answer:
it is 3
Step-by-step explanation:
Answer:
85.1 ft
Step-by-step explanation:
The extreme water slide forms a 20 angle with the tower it leans against 80 feet above the ground find the length of the slide x
We solve using the Trigonometric function of Cosine
cos y = adjacent/hypotenuse
y = angle = 20°
Adjacent = 80 ft
Hypotenuse = ?
cos 20 = 80/Hypotenuse
Hypotenuse = 80/cos 20
x = 85.134221798 ft
Approximately = 85.1 ft
Length of the slide = 85.1 ft