Answer: 11.8
Step-by-step explanation:
 
        
             
        
        
        
Hello,
There is a mistake: it is 816 cm² !!! (an area)
length are multiplied by 2,
so area are mutiplied by 2²=4
Area B=816*4=3264 (cm²)
        
             
        
        
        
Answer:
15/4 +6y
Step-by-step explanation:
See Image below:) 
 
        
             
        
        
        
Answer:
y = 5
Step-by-step explanation:
A line parallel to the x- axis has equation 
y = c
Where c is the value of the y- coordinates the line passes through
The line passes through (1, 5) with y- coordinate of 5, thus
y = 5 ← equation of line
 
        
             
        
        
        
The object should be placed 20/cm from the lens so as to form its real image on the screen
<h3>Mirror equation</h3>
The mirror equation is given according to the expression below;
1/f = 1/u + 1/v
where
f is the focal length
u is the object distance
v is the image distance
Given the following parameters
f = 5cm
v = 20cm
Required
object distance u
Substitute
1/5 = 1/u +1/20
1/u = 1/5-1/20
1/u = 3/20
u = 20/3 cm
Hence the object should be placed 20/cm from the lens so as to form its real image on the screen
Learn more on mirror equation here; brainly.com/question/27924393
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