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Finding the Fourth Proportional to 221.56, 330 and 210

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Solution

The fourth proportional to 221.56, 330 and 210 is: 312.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.56 : 330 = 210 : x
  2. Step 2: Convert to fraction form
    221.56/330 = 210/x
  3. Step 3: Cross multiply
    221.56x = 330 × 210
  4. Step 4: Simplify right side
    221.56x = 69,300
  5. Step 5: Solve for x
    x = 69,300/221.56
  6. Step 6: Final answer
    x = 312.78

Related Problems

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Half scale
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.