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Finding the Fourth Proportional to 1,113.64, 1,670.36 and 420.28

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Solution

The fourth proportional to 1,113.64, 1,670.36 and 420.28 is: 630.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,113.64 : 1,670.36 = 420.28 : x
  2. Step 2: Convert to fraction form
    1,113.64/1,670.36 = 420.28/x
  3. Step 3: Cross multiply
    1,113.64x = 1,670.36 × 420.28
  4. Step 4: Simplify right side
    1,113.64x = 702,018.90
  5. Step 5: Solve for x
    x = 702,018.90/1,113.64
  6. Step 6: Final answer
    x = 630.38

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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.