The formula is given by;
S.A = 2lh + 2hw + 2lw
where l is the length
h is the height
w is the width
From the question diagram;
l = 1 3/10 = 13/10 when changed to improper fraction
w= 1 2/5 = 7/5 when changed to improper fraction
h = 1 1/5 = 6/5 when changed to improper fraction
Substituting the values into the formula;
S.A = 2(13/10)(6/5) + 2(6/5)(7/5) + 2(13/10)(7/5)
Then we go ahead and evaluate;
S.A = 156/50 + 84/25 + 182/50
=78/25 + 84/25 + 91/25
=253/25
= 10 3/25
