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Finding the Fourth Proportional to 1,387.17, 2,079.93 and 521.28

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Solution

The fourth proportional to 1,387.17, 2,079.93 and 521.28 is: 781.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.17 : 2,079.93 = 521.28 : x
  2. Step 2: Convert to fraction form
    1,387.17/2,079.93 = 521.28/x
  3. Step 3: Cross multiply
    1,387.17x = 2,079.93 × 521.28
  4. Step 4: Simplify right side
    1,387.17x = 1,084,225.91
  5. Step 5: Solve for x
    x = 1,084,225.91/1,387.17
  6. Step 6: Final answer
    x = 781.61

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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.