Please and thank you help with math!!

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?