Given that Jiao is a Chinese student visiting family in the United States, and she spent $ 79 on dinner for her family one evening, if the exchange rate that day is UDS to CNY = 6.51, to determine approximately how much money did she spend in CNY the following calculation must be performed:
Wa=0.5Wb, Ha=20, Hb is unkown the area of rectangle a is : Wa*20 the area of rectangle b is : Wb*Hb Rectangle a has 7 times the area of rectangle b: Wa*20=7*Wb*Hb Replace Wa with 0.5Wb: 0.5Wb*20=7Wb*Hb => Hb=10/7
