Conic Sections Question 193
If the eccentricity of an ellipse be 5/8 and the distance between its foci be 10, then its latus rectum is 5/4
Options:
A) 39/4
12
15
D) 37/2
Show Answer
Answer:
Correct Answer: A
Solution:
$ a=\frac{10}{\frac{2.5}{8}}=8 $ , $ b=8\sqrt{1-\frac{25}{64}}=8\frac{\sqrt{39}}{8} $
Latus rectum $ =\frac{2b^{2}}{a}=\frac{2\times 39}{8}=\frac{78}{8} $ .
BETA
