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Finding the Fourth Proportional to 765.46, 1,055.73 and 645.40

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Solution

The fourth proportional to 765.46, 1,055.73 and 645.40 is: 890.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    765.46 : 1,055.73 = 645.40 : x
  2. Step 2: Convert to fraction form
    765.46/1,055.73 = 645.40/x
  3. Step 3: Cross multiply
    765.46x = 1,055.73 × 645.40
  4. Step 4: Simplify right side
    765.46x = 681,368.14
  5. Step 5: Solve for x
    x = 681,368.14/765.46
  6. Step 6: Final answer
    x = 890.14

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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.