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Finding the Fourth Proportional to 1,287.02, 1,929.90 and 637.40

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Solution

The fourth proportional to 1,287.02, 1,929.90 and 637.40 is: 955.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.02 : 1,929.90 = 637.40 : x
  2. Step 2: Convert to fraction form
    1,287.02/1,929.90 = 637.40/x
  3. Step 3: Cross multiply
    1,287.02x = 1,929.90 × 637.40
  4. Step 4: Simplify right side
    1,287.02x = 1,230,118.26
  5. Step 5: Solve for x
    x = 1,230,118.26/1,287.02
  6. Step 6: Final answer
    x = 955.79

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.