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Finding the Fourth Proportional to 399.72, 550.80 and 312.24

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Solution

The fourth proportional to 399.72, 550.80 and 312.24 is: 430.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.72 : 550.80 = 312.24 : x
  2. Step 2: Convert to fraction form
    399.72/550.80 = 312.24/x
  3. Step 3: Cross multiply
    399.72x = 550.80 × 312.24
  4. Step 4: Simplify right side
    399.72x = 171,981.79
  5. Step 5: Solve for x
    x = 171,981.79/399.72
  6. Step 6: Final answer
    x = 430.26

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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.