plz help me to answer the following questions;;i need the steeps;;thz for your help=)
1)If the radius of a circle is increased by 10%,find the percentage increase in its area.
2)If the height of a triangle is increased by 30% while its base is dreased by 25%,what is the percentage change in its area?
3)There are 800 students in a school,37.5% of them are girls.If the number of boys and girls are increased by 20% and 10% respectively,What is the percentage change in the number of students?