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Finding the Fourth Proportional to 851.80, 1,277.70 and 390.10

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Solution

The fourth proportional to 851.80, 1,277.70 and 390.10 is: 585.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.80 : 1,277.70 = 390.10 : x
  2. Step 2: Convert to fraction form
    851.80/1,277.70 = 390.10/x
  3. Step 3: Cross multiply
    851.80x = 1,277.70 × 390.10
  4. Step 4: Simplify right side
    851.80x = 498,430.77
  5. Step 5: Solve for x
    x = 498,430.77/851.80
  6. Step 6: Final answer
    x = 585.15

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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.