Question

If cos thita =4/5 then find sec thita​

Answer 1

Answer:

cos thita = 1/sec thita

so, if cos thita = 4/5

then , sec thita = 5/4

Answer 2

Note: see answer from website

Figure

$\setlength{\unitlength}{1cm}\begin{picture}(6,5)\linethickness{.4mm}\put(1,1){\line(1,0){4.5}}\put(1,1){\line(0,1){3.5}}\qbezier(1,4.5)(1,4.5)(5.5,1)\put(.3,2.5){\large\bf 3}\put(2.8,.3){\large\bf 4}\put(1.02,1.02){\framebox(0.3,0.3)}\put(.7,4.8){\large\bf A}\put(.8,.3){\large\bf B}\put(5.8,.3){\large\bf C}\qbezier(4.5,1)(4.3,1.25)(4.6,1.7)\put(3.8,1.3){\large\bf \theta }\end{picture}$

From above figure,

$\rm { Perpendicular = \sqrt{ hypotenuse^{2} - base^{2}}}$

$\large\rm { AB = \sqrt{AC^{2} - BC^{2}}}$

$\large\rm { AB = 3}$

$\large\rm { \sec \theta = \frac{AC}{BC}}$

$\Large\rm { \therefore \sec \theta = \frac{5}{4}}$