The figure in the question is a combination of both parallelogram and a semicircle.
So, we will find the Area of both the parallelogram and the semicircle and then add them up to get the Area of the given figure.
Formular for the Area of a Parallelogram = Base x Height
A = B x H
B = 26
H = 12
Area = 26 x 12
Area = 312
The Area of the Parallelogram = 312
The formular for the Area of a Semicircle is = 1/2 Pi r^2
Area = 1/2 Pi r^2
The radius is not given but we have the diameter.
Radius r = diameter/2
Diameter = 20
Radius = 20/2
Radius = 10
Area of the semicircle = 1/2 x 3.142 x 10
= 1/2 x 31.42
Area = 15.71
The Area of the Semicircle = 15.71
The Area of the given figure = Area of the Parallelogram + Area of the Semicircle
The Area of the given figure = 312 + 15.71
Therefore the Area of the given figure = 327.71