Answer: 47.36 feet.
Explanation:
When two quantities x and y are directly proportional , then the equation that shows direct variation is given by :-
![(x_1)/(y_1)=(x_2)/(y_2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lk7okdvgv8lu2zceghaujy4vv53fo1eo2t.png)
Given : The shadow cast by an object on a sunny day is directly proportional to the height of the object.
Let x be the height of tree.
According to the the given question , we have
![(x)/(34)=(78)/(56)\\\\\Rightarrow\ x=(78*34)/(56)\\\\\Rightarrow\ x=47.3571428571\approx47.36](https://img.qammunity.org/2020/formulas/mathematics/high-school/993w29zdxfap5dz8qrl3fhsdgwd7azthyc.png)
Hence, the height of tree = 47.36 feet.