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Finding the Fourth Proportional to 918.80, 1,377.77 and 398.78

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Solution

The fourth proportional to 918.80, 1,377.77 and 398.78 is: 597.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.80 : 1,377.77 = 398.78 : x
  2. Step 2: Convert to fraction form
    918.80/1,377.77 = 398.78/x
  3. Step 3: Cross multiply
    918.80x = 1,377.77 × 398.78
  4. Step 4: Simplify right side
    918.80x = 549,418.24
  5. Step 5: Solve for x
    x = 549,418.24/918.80
  6. Step 6: Final answer
    x = 597.98

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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.