Answer:
9 feet
Explanation:
Given: area of kite= 3 ft²
Tail= 3 times longer than the kites long diagonal.
Measures of short diagonal(d_2)= 2 feet
Let´s assume the measure of long diagonal (d_1) be "x"
Formula; Area of kite=
![(d_1* d_2)/(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/a20mm2nkyaczjxxyiipeb5injxvxfcn4cu.png)
⇒
![3= (x* 2)/(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/e8d5lzuih2zcp8e3dp87a2hz51qfzrupwc.png)
∴
![x= 3\ feet](https://img.qammunity.org/2021/formulas/mathematics/high-school/m3ledm3a66p10docn1kyzkh8etu1lik1kc.png)
Hence, measure of long diagonal is 3 feet.
Now, finding the length of kite tail.
as given tail is to be 3 times longer than the kites long diagonal.
Length of kite´s tail=
![3* 3](https://img.qammunity.org/2021/formulas/mathematics/high-school/p2ynnba7nw31rvr7knc3lec7x36yevs4xl.png)
∴ Length of kite´s tail=
![9\ feet](https://img.qammunity.org/2021/formulas/mathematics/high-school/azevlgnbhbvk8vhq6appk9a5ulgai245b0.png)
Hence, 9 feet long should be the kite tail.