Respuesta :
Finding the proportionality constant :
- y = k/x²
- 64 = k/(1/4)²
- k = 4
Finding y when x = 7 :
- y = 4/(7)²
- y = 4/49
The value of y is 4/49 when x = 7.
[tex]y = \frac{k}{ {x}^{2} } \\ \\ 64 = \frac{k}{ { (\frac{1}{4}) }^{2} } \\ \\ 64 = \frac{k}{ \frac{1}{16} } \\ \\ 64 = 16k \\ \\ k = \frac{64}{16} \\ \\ k = 4.[/tex]
Finding 'y'
[tex]y = \frac{4}{ {7}^{2} } \\ \\ y = \frac{4}{49} .[/tex]