@cirnohappy@JefferyDoomer I inserted the doubled area of CBK into a "find diagonal from square area) formula that gave me CB (right screenshot) and inserted that formula into the hexagon area formula (left screenshot). I did the square area in my head by doubling the CBK area.
Are there really teachers still saying "you won't have a calculator everywhere you go" when the calculators we need for daily life can easily run Doom?