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Finding the Fourth Proportional to 1,678.32, 2,515.28 and 856.80

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Solution

The fourth proportional to 1,678.32, 2,515.28 and 856.80 is: 1,284.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,678.32 : 2,515.28 = 856.80 : x
  2. Step 2: Convert to fraction form
    1,678.32/2,515.28 = 856.80/x
  3. Step 3: Cross multiply
    1,678.32x = 2,515.28 × 856.80
  4. Step 4: Simplify right side
    1,678.32x = 2,155,091.90
  5. Step 5: Solve for x
    x = 2,155,091.90/1,678.32
  6. Step 6: Final answer
    x = 1,284.08

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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.