To find the perimeter of the figure, we need to sum the lengths of all its outer edges.
Let's identify the lengths of the exterior sides:
- The left vertical side of rectangle B: 5 cm
- The bottom horizontal side of rectangle B: 12 cm
- The right vertical side of rectangle B: 5 cm
- The top horizontal side of rectangle B that is exposed (not covered by A): 9 cm
- The left vertical side of rectangle A: 3 cm
- The top horizontal side of rectangle A: 3 cm
- The right vertical side of rectangle A: 3 cm
Now, we sum these lengths to find the total perimeter:
P=5cm+12cm+5cm+9cm+3cm+3cm+3 cm
P=40 cm
Alternatively, we can calculate the perimeter of each rectangle and subtract the overlapping internal boundary.
Perimeter of rectangle B: 2×(12cm+5cm)=2×17cm=34 cm
Perimeter of rectangle A: 2×(3cm+3cm)=2×6cm=12 cm
The length of the common boundary (where A and B meet) is 3 cm. This boundary is counted twice when summing the individual perimeters, so we subtract 2×3 cm from the sum.
Total perimeter = (Perimeter of B) + (Perimeter of A) - 2×(commonboundary)
P=34cm+12cm−2×3 cm
P=46cm−6 cm
P=40 cm
Both methods yield the same result.
Comparing with the given options:
(a) 69 cm
(b) 46 cm
(c) 43 cm
(d) 40 cm
(e) 37 cm
The calculated perimeter matches option (d).
The final answer is 40cm.