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Finding the Fourth Proportional to 856.88, 1,285.20 and 279.76

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Solution

The fourth proportional to 856.88, 1,285.20 and 279.76 is: 419.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.88 : 1,285.20 = 279.76 : x
  2. Step 2: Convert to fraction form
    856.88/1,285.20 = 279.76/x
  3. Step 3: Cross multiply
    856.88x = 1,285.20 × 279.76
  4. Step 4: Simplify right side
    856.88x = 359,547.55
  5. Step 5: Solve for x
    x = 359,547.55/856.88
  6. Step 6: Final answer
    x = 419.60

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1.5x scale

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.