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Finding the Fourth Proportional to 877.12, 1,210.40 and 478.78

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Solution

The fourth proportional to 877.12, 1,210.40 and 478.78 is: 660.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.12 : 1,210.40 = 478.78 : x
  2. Step 2: Convert to fraction form
    877.12/1,210.40 = 478.78/x
  3. Step 3: Cross multiply
    877.12x = 1,210.40 × 478.78
  4. Step 4: Simplify right side
    877.12x = 579,515.31
  5. Step 5: Solve for x
    x = 579,515.31/877.12
  6. Step 6: Final answer
    x = 660.70

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1.5x scale

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.