What is10 + 9

i really dont know

can someone help me

Aperpendicular bisector, cd is drawn through point con ab if the coordinates of point a are (-3, 2) and the coordinates of point b are (7,6), the x-intercept of cd is point lies on cd.

Angles r and s are complementary. the measure of angle r is 31 degrees. which equation can be used to find angle s?

What is the circumference of a circle with an area of 50.24 cm²?