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Finding the Fourth Proportional to 841.70, 1,262.55 and 687.80

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Solution

The fourth proportional to 841.70, 1,262.55 and 687.80 is: 1,031.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    841.70 : 1,262.55 = 687.80 : x
  2. Step 2: Convert to fraction form
    841.70/1,262.55 = 687.80/x
  3. Step 3: Cross multiply
    841.70x = 1,262.55 × 687.80
  4. Step 4: Simplify right side
    841.70x = 868,381.89
  5. Step 5: Solve for x
    x = 868,381.89/841.70
  6. Step 6: Final answer
    x = 1,031.70

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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.