The answer is 20.5632 cm squared
To find this the first step would be to figure out the triangles area. The formula for that is .5(bh). In this case that would be .5(4.8x4.8) which equals 11.52.
Then, you have to find the area of the circle. The formula for this would be

(pie times the radius squared). The radius is not given so you divide the diameter (4.8) by two. This gives you 2.4. 2.4 squared is 5.76. 5.76 times 3.14 is 18.0864. Because it's a semicircle you must also divide 18.0864 by 2. This equals 9.0432.
Adding the two areas gives you 20.5632 cm squared.