Suppose ABC is a right angle triangle where where <ABC = 90 degrees. The ratio between AB and BC is 2.5. Determine the angle <ACB.
According to the question AB/BC = 2.5 tan(<ACB) = AB/BC = 2.5 therefore, <ACB = tan inverse (2.5) = 68.198 degrees. [note: there was no option to upload any image here, so I tried my best to be clear enough in the question and the answer. If the instructions in the questions is followed, the triangle can be drawn at ease. And by the (<) less than sign, I meant the angle. I had to do that because I do not have any such key to draw the actual sign of an angle in the keyboard] I hope that these will be excused. Thanks.
The cut of score for a grade of A+ is 90%. If the total marks of your class test is 55, how many marks do you need to get an A+ ?
Out of 100 marks one needs 90 marks to secure an A+ therefore, Out of 1 mark one needs 90/100 marks to secure an A+ therefore, Out of 55 marks one needs 90*55/100 = 49.5 marks to secure an A+
Why is water an amphoteric compound?
An amphoteric compound is a compound that works as bith acid and base depending on circumstances. According to Bronsted-Lowry concept a compound that donates a proton is an acid and a compound that accepts a proton is a base. If we add HCl to H2O, by accepting a proton H2O forms H3O+. In this case it acted as a base. But while reacting with Na2O, H2O gives up a proton and forms NaOH ans OH-. Here, H2O worked as an acid, This is why water is amphoteric.