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Finding the Fourth Proportional to 1,561.60, 2,342.40 and 978.40

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Solution

The fourth proportional to 1,561.60, 2,342.40 and 978.40 is: 1,467.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,561.60 : 2,342.40 = 978.40 : x
  2. Step 2: Convert to fraction form
    1,561.60/2,342.40 = 978.40/x
  3. Step 3: Cross multiply
    1,561.60x = 2,342.40 × 978.40
  4. Step 4: Simplify right side
    1,561.60x = 2,291,804.16
  5. Step 5: Solve for x
    x = 2,291,804.16/1,561.60
  6. Step 6: Final answer
    x = 1,467.60

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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.