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Finding the Fourth Proportional to 1,035.90, 1,428.84 and 642.87

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Solution

The fourth proportional to 1,035.90, 1,428.84 and 642.87 is: 886.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,035.90 : 1,428.84 = 642.87 : x
  2. Step 2: Convert to fraction form
    1,035.90/1,428.84 = 642.87/x
  3. Step 3: Cross multiply
    1,035.90x = 1,428.84 × 642.87
  4. Step 4: Simplify right side
    1,035.90x = 918,558.37
  5. Step 5: Solve for x
    x = 918,558.37/1,035.90
  6. Step 6: Final answer
    x = 886.72

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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.