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Finding the Fourth Proportional to 1,210.56, 1,670.81 and 686.76

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Solution

The fourth proportional to 1,210.56, 1,670.81 and 686.76 is: 947.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210.56 : 1,670.81 = 686.76 : x
  2. Step 2: Convert to fraction form
    1,210.56/1,670.81 = 686.76/x
  3. Step 3: Cross multiply
    1,210.56x = 1,670.81 × 686.76
  4. Step 4: Simplify right side
    1,210.56x = 1,147,442.04
  5. Step 5: Solve for x
    x = 1,147,442.04/1,210.56
  6. Step 6: Final answer
    x = 947.86

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Half scale
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Double scale
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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.