Apyramid has all sides that are equilateral triangles. each triangle has side lengths of 9 centimeters. if the surface area of the pyramid is 140.4 square centimeters, what is the slant height of the pyramid?

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.