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Note, 1. the rules marked with blue colour, the solutions marked by red; 2. solutions are given shortly.
 
        
             
        
        
        
Answer:
85 nails
Step-by-step explanation:
First, we need to calculate the volume of a single nail. It consists of a circular cylinder and hemispherical part.
The volume of the cylinder πr^2 • h. We are given the diameter of the cylinder (14 mm), so radius is half of that (r = 7 mm) and we are given the height (h = 20 mm).
So, the volume of the cylinder is:
V1 = π • 7^2 • 20
V1 = 3077.2 mm^3
Now for the volume of the hemisphere part. Its volume is half of the sphere:
V2 = (4/3 • πr^3) / 2
Diameter of the sphere is given and it is 21 mm, so the radius is 10.5 mm. So, the volume is:
V2 = (4/3 • π • 10.5^3) / 2
V2 = 2423.3 mm^3
So, the volume of the nail is V1 + V2 which is 5500.5 mm^3
Now let's convert volume of the metal used for making nails. It's given that it is 550.55 cm^3 which is 550550 mm^3.
It is also said that 15% of the volume is wasted, so we are left with 85% of the volume, which is 550550 • 0.85 and that equals to 467967.5 mm^3. So to find a number of nails made from this volume, we divide:
467967.5 / 5500.5 = 85 nails
 
        
             
        
        
        
It is 2x(x-7)+3(x-7) = (2x+3)(x-7)
        
             
        
        
        
Using the distance formula, the distance from:
School to Library (SL) = 5 units.
Library to Park (LP) = 10 units.
<h3>What is the Distance Formula?</h3>
To calculate the distance between two points on a coordinate plane, the distance formula used is: 
.
Given the coordinates of each location as:
- School, S = (0, 4)
 - Library, L = (4, 1)
 - Park, P = (-4, -5)
 
Distance from School to Library (SL):
SL = √[(4−0)² + (1−4)²]
SL = √[(4)² + (−3)²]
SL = √25
SL = 5 units
Distance from Library to Park (LP):
LP = √[(4−(−4))² + (1−(−5))²]
LP = √[(8)² + (6)²]
LP = √100
LP = 10 units
Learn more about the distance formula on:
brainly.com/question/661229
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