Answer:
AB = 5 units
Step-by-step explanation:
Calculate the length using the distance formula
d = [tex]\sqrt{(x_{2}-x_{1})^2+ (y_{2}-y_{1})^2[/tex]
with (x₁, y₁ ) = A(7, 9) and (x₂, y₂ ) = B(3, 12)
AB = [tex]\sqrt{(3-7)^2+(12-9)^2}[/tex]
= [tex]\sqrt{(-4)^2+3^2}[/tex]
= [tex]\sqrt{16+9}[/tex]
= [tex]\sqrt{25}[/tex]
= 5
