Answer:
r = ± [tex]\sqrt{q^2-p^4[/tex]
Step-by-step explanation:
p² = [tex]\sqrt{q^2-r^2}[/tex] ( square both sides )
(p² )² = q² - r²
[tex]p^{4}[/tex] = q² - r² ( subtract q² from both sides )
[tex]p^{4}[/tex] - q² = - r² ( multiply through by - 1 )
q² - [tex]p^{4}[/tex] = r² ( take square root of both sides )
± [tex]\sqrt{q^2-p^4}[/tex] = r
