Answer:
126 cm
Step-by-step explanation:
The real treehouse should be 126 centimeters tall. Given that two students make a model of a treehouse they want to build, and the scale is 1:42, and in the scale model the treehouse store is 3 cm tall, to determine how tall should the real tree house store be the following cross multiplication should be done: 1 = 342 = X(42 x 3) / 1 = X126 / 1 = X126 = XTherefore, the real treehouse should be 126 centimeters tall.