Known: as shown in the figure, in △ ABC, ab = AC, BC = BD, ad = de = EB, then the degree of ∠ A is () A. 30°B. 36°C. 45°D. 50°

Known: as shown in the figure, in △ ABC, ab = AC, BC = BD, ad = de = EB, then the degree of ∠ A is () A. 30°B. 36°C. 45°D. 50°

Let ∠ EBD = x °,  be = De,  EDB = ∠ EBD = x °,  AED = ∠ EBD + ∠ EDB = 2x °,  ad = De,  a = ∠ AED = 2x °,  BDC = ∠ a + ∠ abd = 3x °,  BD = BC,  C = ∠ BDC = 3x °,  AB = AC,  ABC = ∠ C = 3x °,  a + ∠ ABC + ∠ C = 180 °,  2x +

One kilowatt hour of electricity can use a 40 watt bulb for 25.1 hours, and 2.4 kilowatt hours of electricity can make such a lamp

If the measured 40W bulb can be used for 25.1 hours per kilowatt hour, then the 2.4 kilowatt hour electricity can be used for 60.24 hours