D. 12.4
Step-by-step explanation:
We are given the figure with measurements,
PT = y
PA = 7
AB = 15
where P, T, A and B are located as in the figure below.
Now, we know the formula that,
![PT^{2}=PA \times PB](/tpl/images/0327/7531/dc0c3.png)
i.e. ![y^{2}=7 \times (15+7)](/tpl/images/0327/7531/996fa.png)
i.e. ![y^{2}=7 \times 22](/tpl/images/0327/7531/30b62.png)
i.e. ![y^{2}=154](/tpl/images/0327/7531/d30c3.png)
i.e. y= ± 12.4
Since, the length cannot be negative.
Thus, option D i.e. y = 12.4 is correct.
![Find the value or y, rounded to the nearest tenth.12.713.311.712.4](/tpl/images/0327/7531/46a3d.jpg)