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Finding the Fourth Proportional to 431.84, 647.76 and 215.28

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Solution

The fourth proportional to 431.84, 647.76 and 215.28 is: 322.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.84 : 647.76 = 215.28 : x
  2. Step 2: Convert to fraction form
    431.84/647.76 = 215.28/x
  3. Step 3: Cross multiply
    431.84x = 647.76 × 215.28
  4. Step 4: Simplify right side
    431.84x = 139,449.77
  5. Step 5: Solve for x
    x = 139,449.77/431.84
  6. Step 6: Final answer
    x = 322.92

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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.