Question

The value of the ratio of isometric length to true length is ________

(a) 0.141

(b) 0.372

(c) 0.815

(d) 0.642

I had been asked this question during an interview.

My question comes from Isometric Axes, Lines and Planes in chapter Isometric Projection of Engineering Drawing

Answer 1

The correct answer is (c) 0.815

The best I can explain: If we represent a cube in isometric view the diagonal of upper face of cube is equal to the true length of the diagonal. From it by drawing an actual square around it and then calculating it gives (1/cos 30)/ (1/cos 45) =isometric /true =0.815.