The shape of the room is not a square.
Pythagorean Theorem: 17^2+17^2= 578, square root 578 and you'll get 24.04.
The length of the diagonal of the floor of the room in the plan should have been 24.04 in order to be a square.
.15 repeating which is the 2nd one
You should do it i think it finds out about if u cheated or not
Selling price of the chair = 1440 rupees
Percentage of loss made by the shopkeeper = 10%
Let us assume the price at which the shopkeeper bought the chair = x
Then
90% * x = 1440 rupees
(90/100) * x = 1440 rupees
9x/10 = 1440 rupees
9x = 1440 * 10 rupees
9x = 14400 rupees
x = 14400/9 rupees
= 1600 rupees
So the price at which the shopkeeper bought the chair was 1600 rupees. I hope the procedure is clear enough for you to inderstand.