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Finding the Fourth Proportional to 907.61, 1,360.80 and 420.39

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Solution

The fourth proportional to 907.61, 1,360.80 and 420.39 is: 630.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    907.61 : 1,360.80 = 420.39 : x
  2. Step 2: Convert to fraction form
    907.61/1,360.80 = 420.39/x
  3. Step 3: Cross multiply
    907.61x = 1,360.80 × 420.39
  4. Step 4: Simplify right side
    907.61x = 572,066.71
  5. Step 5: Solve for x
    x = 572,066.71/907.61
  6. Step 6: Final answer
    x = 630.30

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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.