Yes it is The hypotenuse is 10 cms long.
Because its a right angled triangle ( 90 angle) the hypotenuse will be 10 cms long - it will obey the Pythagoras theorem:-
10^2 = 8^2 + 6^2
There is only one right angled triangle with these measurements but there are many of them which have sides in same ratio
for example
3, 4 and 5
9,12 and 15
12, 16 and 20 and so on..
.3455 is the correct answer.
Let
In order to prove this by induction, we first need to prove the base case, i.e. prove that P(1) is true:
So, the base case is ok. Now, we need to assume 
and prove 
.
states that
Since we're assuming , we can substitute the sum of the first n terms with their expression:
Which terminates the proof, since we showed that
as required
and then there's a line with 2y right under that expression
