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Finding the Fourth Proportional to 1,139.62, 1,572.64 and 642.22

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Solution

The fourth proportional to 1,139.62, 1,572.64 and 642.22 is: 886.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.62 : 1,572.64 = 642.22 : x
  2. Step 2: Convert to fraction form
    1,139.62/1,572.64 = 642.22/x
  3. Step 3: Cross multiply
    1,139.62x = 1,572.64 × 642.22
  4. Step 4: Simplify right side
    1,139.62x = 1,009,980.86
  5. Step 5: Solve for x
    x = 1,009,980.86/1,139.62
  6. Step 6: Final answer
    x = 886.24

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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.