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Finding the Fourth Proportional to 840.10, 1,259.49 and 429.40

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Solution

The fourth proportional to 840.10, 1,259.49 and 429.40 is: 643.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.10 : 1,259.49 = 429.40 : x
  2. Step 2: Convert to fraction form
    840.10/1,259.49 = 429.40/x
  3. Step 3: Cross multiply
    840.10x = 1,259.49 × 429.40
  4. Step 4: Simplify right side
    840.10x = 540,825.01
  5. Step 5: Solve for x
    x = 540,825.01/840.10
  6. Step 6: Final answer
    x = 643.76

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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.