B2 First-grader Nina was playing with dominoes. The dominoes were rectangular in shape, with a width of $3 \mathrm{~cm}$ and a length of $7 \mathrm{~cm}$. She arranged them along the edge of the table as shown in the picture. The longer side of the domino makes an angle of $40^{\circ}$ with the edge of the table. How far is the outermost corner of the domino from the edge of the table? The result should be accurate to the nearest millimeter.

(6 points)

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B2. The distance is the length of the segment $R M$. From the image, we can see that: $|R M|=|R A|+|A M|$, angle $M D A=50^{\circ}, \operatorname{angle} R B A=40^{\circ}$. We consider $\sin 50^{\circ}=\frac{|M A|}{\mid A D}$, from which we express $|M A|=$ $|A D| \cdot \sin 50^{\circ}$. We calculate $|M A|=2,298 \mathrm{~cm}$. We also use $\sin 40^{\circ}=\frac{|R A|}{\mid B A}$. We express $|R A|=|B A| \cdot \sin 40^{\circ}=4,5 \mathrm{~cm}$. We then calculate $|R M|=2,298+4,5=6,8 \mathrm{~cm}$. 

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Calculation of $|R A|=|B A| \cdot \sin 40^{\circ}=4,5 \mathrm{~cm} \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots$

![](https://cdn.mathpix.com/cropped/2024_06_07_c987701c9bb62194911fg-13.jpg?height=57&width=1685&top_left_y=1339&top_left_x=228)