The equation which could be used to find the value of x is; cos 49° = x over 55; option A.
An equation is an expression which is used to show the relationship between two or more terms and this relationship is that the terms are equal.
An equation has two sides, the left hand side and the right hand side. An equation also contains an equal sign.
If an unknown variable is present in one or more of the sides, the value of that unknown can be found algebraically.
In the given question, the triangle DEF is a right-angled triangle, where angle E is a right angle.
The side DF measures 55, the side DE measures x, and the angle D measures 49°.
This follows that the the hypotenuse is DF and the adjacent side is D.
Using the trigonometric ratios;
where θ = 49°
cos 49° = x/55
x = cos 49° * 55
x = 36
In conclusion, the value of x is obtained by using trigonometrical ratios.
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Note that the complete question is given below:
Which equation could be used to find the value of x?
Triangle DEF where angle E is a right angle. DE measures x. DF measures 55. Angle D measures 49 degrees.
cos 49° = x over 55
cos 49° = 55 over x
sin 49° = x over 55
sin 49° = 55 over x
