Concave mirror reflection, problems with drawing setup

[radish]

Homework Statement

I had a homework where a concave mirror with a focal point of -4 centimeters had an object away from it by 5 centimeters (1 cm after the focal point). I decided to solve the problem by drawing it this time and not by using the equations and its giving me a different answer than the equations.

Relevant Equations

1/f=1/Di+1/Do
f= focal point
Di= distance of image
Do= distance of object

1/f = 1/Di + 1/Do
1/Di = 1/f - 1/Do
1/Di = 1/4 - 1/5
1/Di = 1/20
Di = 20 cm
In my drawing i had a focal point of 4 so a center of circumference of 8 and I had an object with a height of 1 cm placed 1 cm after the focal point, so 5 cm, away from the mirror. The distance of the image that i could measure was about 17.3 cm. Am i doing anything wrong?

 

[Gordianus]

Can you attach your drawing?

 

[radish]

Can you attach your drawing?

alright sure.
the closest line to the mirror is the point of convergence, the second line is the object, my lines pass by the focal point and the center of circumference. the point of convergence where the two lines going from the object meet is about 17.3 cm even tho its supposed to be 20cm. thank you for answering.

 

[Gordianus]

My eyes are too old and I can't see the mirror, the optical axis, the focal point and so on. Can you post a better drawing?

 

[radish]

Hope this helps.

 

[BvU]

Homework Statement: I had a homework where a concave mirror with a focal point of -4 centimeters had an object away from it by 5 centimeters (1 cm after the focal point). I decided to solve the problem ...

Am i doing anything wrong

Difficult to say if you don't give us the complete problem statement. What is it asking for ?
And you also don't tell us what you are doing: what is CC ?and what is the text (in arabic?)

doing in the picture ?

[edit] !

https://www.physicsforums.com/threads/homework-help-guidelines-for-students-and-helpers.686781/

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