The area of a rectangle is 64 square centimeters. The rectangle is 4 centimeters wide. How long is the rectangle.

The Area is the width times the height : A = w x h;

Then, 64 = w x h;

h = 4 + w;

64 = 4w + w^2;

w^2 + 4w - 64 = 0;

We solve this equation: w1 ≈ 6,24 > 0 (okay); w2 ≈ - 10,24 < 0 (not okay);

Finally, h1 ≈ 10,24;