Many Sides to Cube Problem

* In her Oct. 10 letter, Christy MacBride-Hart contends that the cube in front of the Discovery Science Center in Santa Ana is not a cube because it measures 64 by 64 by 108 feet.

While I do not wish to dispute the findings of a professor of mathematics, in this case the professor is wrong or at least misinformed.

The Discovery Science Center cube will stand on its “point.” Each of the six faces of the cube is indeed 64 by 64 feet. The 108 feet represents the approximate distance from the point on which the cube rests to its highest point, measured diagonally.

Those of us involved with Discovery Science are always concerned about accuracy and thank MacBride-Hart for keeping us on our toes or, in this case, cube.

C.M. “Hoppy” Cunningham

President, J. Ray Construction Co.

Construction Manager

Discovery Science Center

* Christy MacBride-Hart writes that “an object that is 64 by 64 by 108 feet is not a cube because a cube has equal edges.”

I am no mathematical genius, but by applying the Pythagorean theorem on a cube that has a side of 64 feet, I come up with an object 110.85 feet high when balanced on one of its corners.

I did this by first calculating the diagonal distance across one of the faces of the cube: (64x64) + (64x64) = 8,192. The square root of 8,192 is 90.5. This diagonal is one side of another right triangle that has a side of 64 feet, a right triangle whose third side represents the distance from the top to the bottom of a cube balanced on its corner: (64x64) +(90.5x90.5) = 12,286.25. The square root of 12,286.25 is 110.84.

Allowing for rounding the corners of the cube to balance it and for aesthetic reasons, 108 feet is entirely reasonable.

JOHN FORD

San Juan Capistrano

* The height of the cube on a vertex would be the inside diagonal, not the edge of the cube.

I used this in my lesson and had my students calculate what the actual height should be. It was 110.85 feet. And we were wondering how they came up with the 108 feet in the article.

ADRIENNE WOLFE

Math teacher

Polytechnic High School

Long Beach