The diagram shows the cross section of a circular tunnel in the city. Calculate the shaded area.

Solve the following problems:

If each of a 4 subsidiaries of corporation R has been granted a line of credit of Tk. 700,000 and each of the other 3 subsidiaries of Corporation R has been granted a line of credit of Tk. 112,000, what is the average (arithmetic mean) line of credit granted to a subsidiary of corporation R?

Solve the following problems:

A merchant purchased a jacket for Tk. 60 and then determined a selling price that equal purchase price of the jacket plus a markup that was 25 percent of the selling price, Dan sale, the merchant discounted the selling price by 20 percent and sold the jacket. What was the merchant's gross profit on this sale?

A shopkeeper buys 100 mangoes at Tk. 12 each. He sells 60 mangoes at Tk. 17.40 each and r mangoes at Tk. 11.31 each. The shopkeeper makes a profit of at least 10%. Find the least possible value of x.

Factories  $4t^2+35t-9$

Lamia owns a hairdressing salon. She borrows Tk. 2,500 from a bank to make improvements to her beauty salon. She is charged 4.5% per year compound interest. She pays the money back after 3 years. Calculate the total amount Lamia must pay to the bank.