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Finding the Fourth Proportional to 1,210.80, 1,670.72 and 686.73

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Solution

The fourth proportional to 1,210.80, 1,670.72 and 686.73 is: 947.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210.80 : 1,670.72 = 686.73 : x
  2. Step 2: Convert to fraction form
    1,210.80/1,670.72 = 686.73/x
  3. Step 3: Cross multiply
    1,210.80x = 1,670.72 × 686.73
  4. Step 4: Simplify right side
    1,210.80x = 1,147,330.11
  5. Step 5: Solve for x
    x = 1,147,330.11/1,210.80
  6. Step 6: Final answer
    x = 947.58

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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.