Answer:
a = 2[tex]\sqrt{7}[/tex]
Step-by-step explanation:
Given
[tex]\sqrt{28}[/tex] = [tex]\sqrt{a^{2} }[/tex], then
a² = 28 ( take the square root of both sides )
a = [tex]\sqrt{28}[/tex] = [tex]\sqrt{4(7)}[/tex] = [tex]\sqrt{4}[/tex] × [tex]\sqrt{7}[/tex] = 2[tex]\sqrt{7}[/tex]