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Finding the Fourth Proportional to 1,239.76, 1,710.86 and 687.76

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Solution

The fourth proportional to 1,239.76, 1,710.86 and 687.76 is: 949.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.76 : 1,710.86 = 687.76 : x
  2. Step 2: Convert to fraction form
    1,239.76/1,710.86 = 687.76/x
  3. Step 3: Cross multiply
    1,239.76x = 1,710.86 × 687.76
  4. Step 4: Simplify right side
    1,239.76x = 1,176,661.07
  5. Step 5: Solve for x
    x = 1,176,661.07/1,239.76
  6. Step 6: Final answer
    x = 949.10

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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.