obtuse angle

"You should have seen that movie.... If you have not seen, you are missing something in life...." "These are the 10 books one should read in his lifetime...... Haven't you read any of that?" "Have you still not visited Switzerland? What a lovely country! In your lifetime, you have to visit at least once" "There is a restaurant in Hyderabad. You have not heard of it! What a waste... You should taste their 'biriyani'... It is heavenly...." (Since I am in India, I give this example!). "What are you saying? You don't use an iPhone? I mean, how could you live without it...?" All of us must have come across at least one of these dialogues spoken to us, at some point of time or the other. Am I right? There are billions of movies made in all the languages spoken in the world. May be, around 10% of the movies are worth watching. Even that will work out to millions of movies. It is obvious that no one can see all the good movies i...

These days most of us need a calculator, even to find the answer for 1 + 1. That is a different point altogether! Those days (sigh again...!) we used to do multiplication of big numbers using logarithmic tables (based on the mathematical subject, 'logarithm'). Based on logarithm, a device called 'slide-rule' was used by us in college for assisting us in calculations. That was before the advent of calculators. Now we have in-built calculators in smart phones, our PC / Laptop / Smart watches. In schools those days, the moment we assembled, the first thing we were subjected to was, memorizing the multiplication tables, by repeating them loudly. We used to recite the tables up to 16, by heart (ex: 12 X 16 = 192). But we were nothing compared to the generation earlier to us. My father used to recite multiplication tables using 'fractions' (ex: 1/8 X 1/8 = 1/64). He used to tell the name (in Tamil) for 1/64. I do not remember it now. Abacus (an instrument with...