On sunny day, a 5-foot red kangaroo casts a shadow that is 7 feet long. The shadow of a nearby eucalyptus tree is 35 feet long. How do you write and solve a proportion to find the height of the tree?

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Answer 1 · 2018-06-08T20:34:46

Let the height of the kangaroo be #y_1 = 5" ft"#

Let the length of the shadow of the kangaroo be #x_1 = 7" ft"#

Let the unknown height of the tree be #y_2#

Let the length of the shadow of the tree be #x_2 = 35" ft"#

The proportion is:

#y_1/x_1=y_2/x_2#

Solve for #y_2#:

#y_2 = y_1 x_2/x_1#

Substitute in the known values:

#y_2 = (5" ft") (35" ft")/(7" ft")#

#y_2 = 25" ft"#