Step 1: Find 3 spherical objects around your house. These can be anything from a ball to candle (Be creative!!). Try to pick a variety of sizes.
Step 2: Sketch each figure and label the distance around the center (This is the circumference of the largest circular cross section of the sphere). Label with appropriate units.
Step 3: The measurement you just found is the circumference. Calculate the radius of the sphere.
Step 4: Find the surface area of each object. Show all work and label your answers appropriately.
Step 5: Find the volume of each object. Show all work and label your answers appropriately.
Step 6: Submit all work, sketches and answers to your teacher.
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First measure the circumference of the spherical object. Assume we found the length in centimeters. The formula for the radius is
radius=circumference/(2*pi). (in cm)
To find the surface area of the object we use the formula,
surface area=4*pi*radius^2. (in cm^2)
To find the volume we use the formula,
volume = 4/3*pi*radius^3. (in cm^3)
circumference of a donut ball is 12.5 cm.
radius = circumference/(2*pi) = 12.5 cm/(2*3.14)=2.0 cm
surface area = 4*pi*radius^2 = 4*(3.14)*2^2 = 50.3 cm^2
volume = 4/3*pi*radius^3 = 4/3*(3.14)*2^3 = 33.5 cm^3
1) You would find one spherical item. Like a head of lettuce.
2) Mesure the circumference. My lettuce measures out to about 24.5 inches. Draw it on a piece of paper. Label the circumference.
3) To find the radius, you would plug the numbers into C = 2*pi*r, solving for r. So, here:
24.5 = 2*3.14*r
r = 3.90 inches
4) The formula for the surface area of a sphere is SA = 4*pi*r^2. So, plugging in the radius:
SA = 4*3.14*3.9^2 = 191.04 square inches
5) For formula for the volume of a sphere is V = 4/3 * pi * r^3. So, plugging in the radius:
V = 4/3 * 3.14 * 3.9^3 = 248.35 cubic inches.
Make sure you put all the work we did on the paper with your drawing of the head of lettuce.
Then, repeat for 2 different type of spheres. It could be anything. A paper wad you make. Orange. Apple. Bowling ball. Anything spherical.
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