



 
Hi Natalie, In my diagram $C$ is the centre of the sphere and $B$ is the centre of the surface of the water. Triangle $ABC$ is a right triangle and the length of $CA$ is 10 cm. What is the length of $BC?$ What does Pythagoras Theorem give you as the length of $AB?$ What is the area of the surface of the water? In my diagram $h$ is larger than 10 cm, that is the sphere is more than half full. Does the expression for the surface area still hold when $h < 10$ cm? What if $h = 10$ cm? Penny  


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