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Finding the Fourth Proportional to 499.13, 689.13 and 312.90

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Solution

The fourth proportional to 499.13, 689.13 and 312.90 is: 432.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.13 : 689.13 = 312.90 : x
  2. Step 2: Convert to fraction form
    499.13/689.13 = 312.90/x
  3. Step 3: Cross multiply
    499.13x = 689.13 × 312.90
  4. Step 4: Simplify right side
    499.13x = 215,628.78
  5. Step 5: Solve for x
    x = 215,628.78/499.13
  6. Step 6: Final answer
    x = 432.01

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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.