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Finding the Fourth Proportional to 877.22, 1,315.62 and 390

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Solution

The fourth proportional to 877.22, 1,315.62 and 390 is: 584.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.22 : 1,315.62 = 390 : x
  2. Step 2: Convert to fraction form
    877.22/1,315.62 = 390/x
  3. Step 3: Cross multiply
    877.22x = 1,315.62 × 390
  4. Step 4: Simplify right side
    877.22x = 513,091.80
  5. Step 5: Solve for x
    x = 513,091.80/877.22
  6. Step 6: Final answer
    x = 584.91

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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.