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Finding the Fourth Proportional to 1,210.55, 1,670.60 and 686.58

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Solution

The fourth proportional to 1,210.55, 1,670.60 and 686.58 is: 947.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210.55 : 1,670.60 = 686.58 : x
  2. Step 2: Convert to fraction form
    1,210.55/1,670.60 = 686.58/x
  3. Step 3: Cross multiply
    1,210.55x = 1,670.60 × 686.58
  4. Step 4: Simplify right side
    1,210.55x = 1,146,997.12
  5. Step 5: Solve for x
    x = 1,146,997.12/1,210.55
  6. Step 6: Final answer
    x = 947.50

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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.