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Finding the Fourth Proportional to 1,239.50, 1,710.51 and 687.50

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Solution

The fourth proportional to 1,239.50, 1,710.51 and 687.50 is: 948.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.50 : 1,710.51 = 687.50 : x
  2. Step 2: Convert to fraction form
    1,239.50/1,710.51 = 687.50/x
  3. Step 3: Cross multiply
    1,239.50x = 1,710.51 × 687.50
  4. Step 4: Simplify right side
    1,239.50x = 1,175,975.63
  5. Step 5: Solve for x
    x = 1,175,975.63/1,239.50
  6. Step 6: Final answer
    x = 948.75

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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.