Answer: 51.1
Explanation:
In the given picture , we have a right triangle Δ DEF right-angled at ∠F i.e. ∠ F= 90°.
Hypotenuse = DE = 9 units (Side opposite to right angle is hypotenuse)
![\angle{E}=\theta](https://img.qammunity.org/2021/formulas/mathematics/high-school/pey9vd699zjd15t0xqzn48cuuue5hto8h1.png)
and FD = 7 units
According to the trigonometry in a right triangle ,
![\sin x=\frac{\text{Side opposite to x}}{\text{Hypotenuse}}](https://img.qammunity.org/2021/formulas/mathematics/high-school/pnu4dkt037qf0y3ebhwre02bo23eujr6bc.png)
In Δ DEF
So ,
![\sin\theta=(FD)/(DE)](https://img.qammunity.org/2021/formulas/mathematics/high-school/cxnp495f1rtnhsjv6jabml8xldaig043kv.png)
[tex]\sin\theta=\dfrac{7}{9}\\\\ theta =\sin^{-1}(\dfrac{7}{9})\\\\=51.05755873\approx 51.1\ \ [\text{By using sin calculator.}]/tex]
Hence, the approximate value of θ is 51.1.
So the correct answer is "51.1".