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Finding the Fourth Proportional to 745.71, 1,117.35 and 420.90

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Solution

The fourth proportional to 745.71, 1,117.35 and 420.90 is: 630.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    745.71 : 1,117.35 = 420.90 : x
  2. Step 2: Convert to fraction form
    745.71/1,117.35 = 420.90/x
  3. Step 3: Cross multiply
    745.71x = 1,117.35 × 420.90
  4. Step 4: Simplify right side
    745.71x = 470,292.62
  5. Step 5: Solve for x
    x = 470,292.62/745.71
  6. Step 6: Final answer
    x = 630.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.