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Finding the Fourth Proportional to 877.50, 1,315.36 and 390.15

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Solution

The fourth proportional to 877.50, 1,315.36 and 390.15 is: 584.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.50 : 1,315.36 = 390.15 : x
  2. Step 2: Convert to fraction form
    877.50/1,315.36 = 390.15/x
  3. Step 3: Cross multiply
    877.50x = 1,315.36 × 390.15
  4. Step 4: Simplify right side
    877.50x = 513,187.70
  5. Step 5: Solve for x
    x = 513,187.70/877.50
  6. Step 6: Final answer
    x = 584.83

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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.