This is the formula to find the triangle area with sinus property
area = 1/2 × side × side × sin angle between the sides
Input the numbers
area = 1/2 × side × side × sin angle between the sides
area = 1/2 × 20 × 30 × sin 35°
area = 300 × sin 35°
area = 300 × 0.57358
area = 172.07
area = 172.1 ft²