Let us start with the triangle's perimeter:
The triangle's perimeter is the sum of each of its sides:
P = 6mm + 8.5mm + 12mm = 26.5mm
The triangle area is:
A = 1/2 x (base x altitude)
A = 1/2 x (12mm x 4mm)
A = 1/2 x 48 mm^2
A = 24mm^2
Let us continue with the trapezoid's perimeter:
P = 5 in + 8 in + 6 in + 15.5in
P = 34.5in
The trapezoid's area is:
A = 1/2 x (base 1 + base 2) x height
A = 1/2 x (15.5in + 8in) x 4in
A = 1/2 x (23.5in) x 4in
A = 47in^2
Therefore
For the triangle:
Perimeter: 26.5mm.
Area: 24mm^2
For the trapezoid:
Perimeter: 34.5in
Area: 47in^2