 Geometry 101
My 5th grader asked me how to find the volume of a cylinder while eating his breakfast today. He’d been given the answer to a math problem and needed to show how to solve it. My brain immediately froze! Algebra I can do, but I’m seriously challenged when it comes to geometry. I’d normally say talk to Dad. But Dad wasn’t available. No pressure, I had 20 minutes to come up with an explanation.
I can do this, I said to myself and quickly grabbed the math reference book. I found the formula for volume. I’ll just plug in the numbers and prove the solution. Only problem: I needed the value for the radius, and I only had the circumference. So I asked my son how to find the radius from the circumference. “It’s impossible,” he said. “Well … we haven’t learned that yet.”
Feeling super stressed, I said, “Well, I’m not any good at geometry, never have been, but I’ll keep trying.” “It’s OK,” he said. I’ll just tell my teacher I tried to figure this out and asked my mom but she didn’t know.” “No!” I said. “I’ll find the solution!” Seriously, I said to myself, who cares if I can’t do geometry? But I finally found the solution: radius=circumference/pi/2. And the volume of a cylinder is pi times the square of the radius. Phew!
Blessings,
Mary Darr
Editor, MOMSnext ezine
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