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Finding the Fourth Proportional to 648.64, 972.78 and 215.80

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Solution

The fourth proportional to 648.64, 972.78 and 215.80 is: 323.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    648.64 : 972.78 = 215.80 : x
  2. Step 2: Convert to fraction form
    648.64/972.78 = 215.80/x
  3. Step 3: Cross multiply
    648.64x = 972.78 × 215.80
  4. Step 4: Simplify right side
    648.64x = 209,925.92
  5. Step 5: Solve for x
    x = 209,925.92/648.64
  6. Step 6: Final answer
    x = 323.64

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.