Please help me with my lab. It is about thin lenses and spherical mirrors

Magnification hi m ho Magnification di m do Calculated focal length Concave Lens 1. Choose the Diverging Lens (Concave). cometric Optics 2. Using the ruler, measure the distance from x to the center of lens. Record this value as f below: Double this value and record as 2f. f= 2f= 3. Measure the height of object (ho) using the vertical ruler and record below: ho =