The area of the two trianglular ends is
.. (18 cm)*(40 cm) = 720 cm²
The perimeter of the triangular end is
.. 2*41 cm +18 cm = 100 cm
so the lateral area is
.. (100 cm)*(46 cm) = 4600 cm²
The total surface area is the sum of the end area and the lateral area.
.. 720 cm² +4600 cm² = 5320 cm²
