To find the angle sector for cassava in a pie chart, you need to calculate the proportion of cassava's acres relative to the total acres of all crops, and then convert that proportion into degrees.

Total acres of all crops = 2 (rice) + 5 (pineapple) + 3 (cassava) + 11 (cocoa) + 9 (palm oil) = 30 acres.

Proportion of cassava's acres = Acres of cassava / Total acres of all crops = 3 / 30 = 1/10.

To convert the proportion into degrees in a pie chart, you use the fact that a full circle (360 degrees) represents the whole data set (in this case, all the acres). Therefore, the angle sector for cassava in the pie chart is:

Angle sector for cassava = Proportion of cassava's acres 360 degrees = (1/10) 360 degrees = 36 degrees.