A is a point on y-axis whose ordinate is 4 and B is a point on x-axis whose abscissa is -3. Find the length of the line segment AB.

Since, point A is on y-axis so its x-coordinate = 0.

Given,

Ordinate of A = 4.

∴ A = (0, 4).

Since, point B is on x-axis so its y-coordinate = 0.

Given,

Abscissa of B = -3.

∴ B = (-3, 0).

By distance formula,

$\Rightarrow d = \sqrt{(x$2 - x1)^2 + (y2 - y1)^2} \\[1em] \therefore AB = \sqrt{(-3 - 0)^2 + (0 - 4)^2} \\[1em] = \sqrt{(-3)^2 + (-4)^2} \\[1em] = \sqrt{9 + 16} \\[1em] = \sqrt{25} \\[1em] = 5.

Hence, AB = 5 units.