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Finding the Fourth Proportional to 688.15, 1,026.87 and 661.50

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Solution

The fourth proportional to 688.15, 1,026.87 and 661.50 is: 987.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.15 : 1,026.87 = 661.50 : x
  2. Step 2: Convert to fraction form
    688.15/1,026.87 = 661.50/x
  3. Step 3: Cross multiply
    688.15x = 1,026.87 × 661.50
  4. Step 4: Simplify right side
    688.15x = 679,274.51
  5. Step 5: Solve for x
    x = 679,274.51/688.15
  6. Step 6: Final answer
    x = 987.10

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.