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Finding the Fourth Proportional to 877.12, 1,315.85 and 390.17

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Solution

The fourth proportional to 877.12, 1,315.85 and 390.17 is: 585.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.12 : 1,315.85 = 390.17 : x
  2. Step 2: Convert to fraction form
    877.12/1,315.85 = 390.17/x
  3. Step 3: Cross multiply
    877.12x = 1,315.85 × 390.17
  4. Step 4: Simplify right side
    877.12x = 513,406.53
  5. Step 5: Solve for x
    x = 513,406.53/877.12
  6. Step 6: Final answer
    x = 585.33

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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.