Answer:
150 cm
Step-by-step explanation:
The computation of the mean perimeter is presented below:
Let us assume that
X1, X2, X3 and X4 are the four sides of a picture frame
Given
(X1 + X2) ÷ 2 = 30 cm
(X3 + X4) ÷ 2 =45 cm
Now
X1 + X2 = 60 cm
And X3 + X4 = 90 cm
So, the mean perimeter is
= X1 + X2 + X3 + X4
= 60 cm + 90 cm
= 150 cm
The standard deviation is ignored.