Assuming that a person of normal sight can read a printed page at such a distance that the letters subtends an angle of 5 minutes at his eye, find the height of the letters that can be readied at a distance of 12 metres.

Question

jmark · Answer

This can be seen as aright angle triangle with base of 12 meters and angle of 5 minute. 5 minutes = 0.001454441 radians. tan(0.001454441) = h/12 or REQUIRED HEIGHT OF LETTERS = 12*tan(0.001454441) = 0.00030461741 meters. CBSE Maths Syllabus for Class 9: http://cbse.edurite.com/cbse-maths/cbse-maths-syllabus-for-class-9.html