Answer:
The correct answer is option A. 9
Explanation:
Points to remember
The ratio of of corresponding sides of similar triangles are equal.
To find the value of n
From the figure we can see two similar triangles.
Here the ratio of sides is 1/2
Therefore we can write,
39/(n² - 3) = 1/2
2 * 39 = n² - 3
n² = 78 + 3
n = 81
n = ± 9
n = 9
The correct answer is option A. 9