Answer:
x² + y² = 6.25
Step-by-step explanation: 
The standard equation of a circle is ( x – h)² + ( y - k)² = r² where the center is (h, k) and r is the radius.
From your given information that the center is (0, 0) then both h and k are 0. Then r is 2.5, so 
( x – 0)² + ( y - 0)² = (2.5)²
x² + y² = (2.5)²
x² + y² = 6.25
 
        
             
        
        
        
Dr black is standing 13 feet from a streetlamp. The lamp is making his shadow 9 feet long. He estimates that the angle of elevation from the tip of his shadow to the top of the streetlamp is 50° to the nearest foot the streetlamp is about  26 feet tall.
I hope this helps!
 
        
             
        
        
        

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Answer: 75.4	=
  70  
+	5  
+  	0.4
Step-by-step explanation:
Hope this helps :)