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Finding the Fourth Proportional to 761.78, 1,051.17 and 645.14

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Solution

The fourth proportional to 761.78, 1,051.17 and 645.14 is: 890.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    761.78 : 1,051.17 = 645.14 : x
  2. Step 2: Convert to fraction form
    761.78/1,051.17 = 645.14/x
  3. Step 3: Cross multiply
    761.78x = 1,051.17 × 645.14
  4. Step 4: Simplify right side
    761.78x = 678,151.81
  5. Step 5: Solve for x
    x = 678,151.81/761.78
  6. Step 6: Final answer
    x = 890.22

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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.