Geometry
posted by Alex on .
I need help!!!
a hemispherical bowl with radius 25cm contains water whose depth is 10cm. what is the water's surface area

equation of circle radius 25 :
x^2 + y^2 = 25^2 = 625
now what is x when 15 cm from center (which is ten cm from surface)?
x^2 + 225 = 625
x^2 = 400
x = 20
that is our radius at urface
area = pi (20)^2 = 400 pi = 1257 cm^2 
I could also use the formula of a sphere