Help me solve this pythagorean theorem please for 20 points

Length of perpendicular by pythagoras theorem :
P² = H² - B²
P² = 3² - 1²
P² = 9 - 1
P² = 8
P = 2√2
Answer:
[tex]b=2\sqrt{2}[/tex]
Step-by-step explanation:
[tex]a^2+b^2=c^2.[/tex]
[tex]c^2-a^2=b^2.[/tex]
[tex]3^2-1^2=b^2.[/tex]
[tex]9-1=b^2.[/tex]
[tex]b^2=8[/tex]
[tex]b=\sqrt{8}[/tex]
[tex]b=\sqrt{2(4)}[/tex]
[tex]b=2\sqrt{2}[/tex]
Hope this helps!