Answer:
Step-by-step explanation:
Given: ΔDEF is a right angled triangle, right angled at E, DE=21, DF=75 and EF=72.
To find: The trigonometric ratio for cosD.
Solution: We are given that ΔDEF is a right angled triangle, the value of angle of cos is given as:
[tex]CosX=\frac{Base}{Hypotenuse}[/tex]
In the given figure, corresponding to the angle D, the base is DE that is equal to 21 and the hypotenuse is DF that is equal to 75.
Therefore,
[tex]CosD=\frac{DE}{DF}[/tex]
[tex]CosD=\frac{7}{25}[/tex]
Thus, the trigonometric ratio for cosD is [tex]\frac{7}{25}[/tex].
