When the indifference curve is tangent to the budget constraint?

When the indifference curve is tangent to the budget constraint, it indicates that the consumer is maximizing their utility given their budget. At this point, the marginal rate of substitution (MRS) between two goods is equal to the ratio of their prices, meaning the consumer is willing to trade one good for another at the same rate as the market. This tangency point represents the optimal consumption bundle, where the consumer achieves the highest level of satisfaction without exceeding their budget.