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Finding the Fourth Proportional to 856.10, 1,284.15 and 640.10

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Solution

The fourth proportional to 856.10, 1,284.15 and 640.10 is: 960.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.10 : 1,284.15 = 640.10 : x
  2. Step 2: Convert to fraction form
    856.10/1,284.15 = 640.10/x
  3. Step 3: Cross multiply
    856.10x = 1,284.15 × 640.10
  4. Step 4: Simplify right side
    856.10x = 821,984.42
  5. Step 5: Solve for x
    x = 821,984.42/856.10
  6. Step 6: Final answer
    x = 960.15

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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.