Answer:
The value of x would be 20
Step-by-step explanation:
To solve this triangle, we need to first note that all triangles have 180 degrees. So we can add these all together and set equal to 180. 
40 + 3x + 4x = 180
40 + 7x = 180
7x = 140
x = 20
 
        
             
        
        
        
Answer:
452.16
Step-by-step explanation:
the equation is A=nr^2
 
        
             
        
        
        
Answer:
yes
Step-by-step explanation:
Yes this triangle is right angled and can be justified using the Pythagorean theorem. The theorem states that:  . Substitute using the given values:
. Substitute using the given values:
(9^2)+(12^2)=15^2
81 + 144 = 255
255 = 255.
It satisfies the theorem therefore it is a right angle triangle. 
 
        
             
        
        
        
Answer:
5x/3y2
Step-by-step explanation: