Answer:
The value of s is 17.7mm.
Step-by-step explanation:
Given that perimeter of a shape happens when all sides are add up together. So for this question :
[tex]perimeter = 7 + 19.9 + s + s[/tex]
[tex]perimeter = 26.9 + 2s[/tex]
Let perimeter = 62.3mm,
[tex]62.3 = 26.9 + 2s[/tex]
[tex]2s = 62.3 - 26.9[/tex]
[tex]2s = 35.4[/tex]
[tex]s = 35.4 \div 2[/tex]
[tex]s = 17.7mm[/tex]
