Since currencies are always traded in pairs, the exchange rate always affects the value of the currencies in pairs with respect to each other. If the price of the base currency (which you want to buy) is growing, the value of the quoted currency (which you pay for the base currency ) falls in relation to the first.
For example, if you want to buy the euro for US dollars (in the EUR/USD currency pair ) at a rate of 1 euro / 1.25 dollars, you need to pay $ 1.25 to buy 1 euro. If the euro grows, the exchange rate may to become equal, for example, 1 euro / 1.30 dollars. This means that the euro rose in price, and now you need to pay $ 1.30 to buy 1 euro. In other words, the euro has risen in price against the US dollar.