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Finding the Fourth Proportional to 528, 728.64 and 321.12

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Solution

The fourth proportional to 528, 728.64 and 321.12 is: 443.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    528 : 728.64 = 321.12 : x
  2. Step 2: Convert to fraction form
    528/728.64 = 321.12/x
  3. Step 3: Cross multiply
    528x = 728.64 × 321.12
  4. Step 4: Simplify right side
    528x = 233,980.88
  5. Step 5: Solve for x
    x = 233,980.88/528
  6. Step 6: Final answer
    x = 443.15

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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.