The transformation curve slopes indicate that

The slope of the transformation curve indicates the opportunity cost of producing one commodity in terms of the other. Opportunity cost refers to the cost of forgoing the next best alternative. In this case, it refers to the cost of producing one commodity instead of the other. The slope of the curve represents the rate at which one commodity can be exchanged for the other. Therefore, the steeper the slope, the higher the opportunity cost of producing one commodity in terms of the other. Conversely, the flatter the slope, the lower the opportunity cost of producing one commodity in terms of the other.