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Finding the Fourth Proportional to 528.21, 728.96 and 318.40

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Solution

The fourth proportional to 528.21, 728.96 and 318.40 is: 439.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    528.21 : 728.96 = 318.40 : x
  2. Step 2: Convert to fraction form
    528.21/728.96 = 318.40/x
  3. Step 3: Cross multiply
    528.21x = 728.96 × 318.40
  4. Step 4: Simplify right side
    528.21x = 232,097.45
  5. Step 5: Solve for x
    x = 232,097.45/528.21
  6. Step 6: Final answer
    x = 439.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.