Question

the dimension of photograph are 30cmx20cm what length of wooden frame is needed to frame the pictures

Answer 1

Here is your answer:-

Height is 30 cm
Length is 20 cm
Then ,

$30 \times 2 \\ 20 \times 2 \\ 60 + 40 \\ 100$
100 is answer to your question

Answer 2

31×21.........is the dimension in which the photo can be fitted