The actual length of a painting was 2 m. What is the length of the photograph if the scale used is 1 mm:20 cm.
The actual length of the painting was 2 m or 2×100=200cm
[∴ 1 m=100 cm]
Scale used in the painting =1 mm:20 cm
Hence, length of painting in photograph = Scale × Actual Size
[Because Scale =size~drawnactual~size]
Therefore, the length of painting in photograph =10 mm.