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Finding the Fourth Proportional to 743.12, 1,025.38 and 428.40

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Solution

The fourth proportional to 743.12, 1,025.38 and 428.40 is: 591.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    743.12 : 1,025.38 = 428.40 : x
  2. Step 2: Convert to fraction form
    743.12/1,025.38 = 428.40/x
  3. Step 3: Cross multiply
    743.12x = 1,025.38 × 428.40
  4. Step 4: Simplify right side
    743.12x = 439,270.20
  5. Step 5: Solve for x
    x = 439,270.20/743.12
  6. Step 6: Final answer
    x = 591.11

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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.