In a reflection, the shape is flipped. In the first pair, the corresponding sides as shown by the lines, and the corresponding angle are already in the same position. In the second pair, Δ MLN can be reflected so that line LN match with EG and line LM matches with line EF. ∠L and ∠E will also be mapped to each other when one triangle is reflected.
For this case, the radius of whole coconut is 2.5 inches (which is 5 inches / 2). You have to subtract the thickness of the coconut from this radius for you to get the volume of the space for coconut milk.
