Step-by-step explanation:
Use Sine Rule.
[tex] \frac{r}{ \sin(90) } = \frac{4.9}{ \sin(45) } \\ \: cross \: multiply \\ rsin(45) = 4.9sin(90) \\ r = \frac{4.9sin(90)}{ \sin(45) } \\ r = \frac{49 \sqrt{2} }{10} [/tex]
Use same rule to find n1.
[tex] \frac{n1}{sin45} = \frac{4.9}{sin(45)} \\ cross \: multiply \\ n1 \sin(45) = 4.9sin(45) \\ n1 = 4.9[/tex]
Therefore Perimeter of triangle = Sum of all sides.
[tex]r + n1 + 4.9 = \frac{49 \sqrt{2} }{10} + 4.9 + 4.9 \\ = \frac{49 \sqrt{2} }{10} + \frac{49}{5} [/tex]