ASAP HELP 100 POINTS

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)

Apool measures 12.3 feet by 16.6 feet. if the longer wall of the pool has a diagonal of 17.8 feet, what is the volume of the pool? (round to nearest tenth)

When you find the area of a triangle do you use in. or in2