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Finding the Fourth Proportional to 665.07, 918.90 and 499

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Solution

The fourth proportional to 665.07, 918.90 and 499 is: 689.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.07 : 918.90 = 499 : x
  2. Step 2: Convert to fraction form
    665.07/918.90 = 499/x
  3. Step 3: Cross multiply
    665.07x = 918.90 × 499
  4. Step 4: Simplify right side
    665.07x = 458,531.10
  5. Step 5: Solve for x
    x = 458,531.10/665.07
  6. Step 6: Final answer
    x = 689.45

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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.