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Finding the Fourth Proportional to 1,129.63, 1,558.89 and 687.45

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Solution

The fourth proportional to 1,129.63, 1,558.89 and 687.45 is: 948.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,129.63 : 1,558.89 = 687.45 : x
  2. Step 2: Convert to fraction form
    1,129.63/1,558.89 = 687.45/x
  3. Step 3: Cross multiply
    1,129.63x = 1,558.89 × 687.45
  4. Step 4: Simplify right side
    1,129.63x = 1,071,658.93
  5. Step 5: Solve for x
    x = 1,071,658.93/1,129.63
  6. Step 6: Final answer
    x = 948.68

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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.