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Finding the Fourth Proportional to 1,355.21, 1,870.12 and 765.64

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Solution

The fourth proportional to 1,355.21, 1,870.12 and 765.64 is: 1,056.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,355.21 : 1,870.12 = 765.64 : x
  2. Step 2: Convert to fraction form
    1,355.21/1,870.12 = 765.64/x
  3. Step 3: Cross multiply
    1,355.21x = 1,870.12 × 765.64
  4. Step 4: Simplify right side
    1,355.21x = 1,431,838.68
  5. Step 5: Solve for x
    x = 1,431,838.68/1,355.21
  6. Step 6: Final answer
    x = 1,056.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.