Final answer:
Mark can use a measuring tape to determine the height of a tree and mathematical proportion using cross multiplication to find the unknown height from a model.
Step-by-step explanation:
Mark wants to determine the height x of a nearby tree. To accurately measure the height, one could use a measuring tape, ideally suited for measurements in feet or yards, as a tree's height typically falls within such units. When dealing with the proportion related to heights and models, cross multiplication is a valuable mathematical tool to find the unknown height.
For example, if you have the proportion 1 cm/0.5 m=75 cm/x m for a model, you would cross multiply to get 1x=0.5×75, simplifying to x=37.5 m to determine the tree height based on the model. Similarly, for 1 cm/0.5 m=150 cm/x m, the cross multiplication leads to x=75 m, another example of using proportions to find height.