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Finding the Fourth Proportional to 787.40, 1,085.85 and 507.72

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Solution

The fourth proportional to 787.40, 1,085.85 and 507.72 is: 700.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.40 : 1,085.85 = 507.72 : x
  2. Step 2: Convert to fraction form
    787.40/1,085.85 = 507.72/x
  3. Step 3: Cross multiply
    787.40x = 1,085.85 × 507.72
  4. Step 4: Simplify right side
    787.40x = 551,307.76
  5. Step 5: Solve for x
    x = 551,307.76/787.40
  6. Step 6: Final answer
    x = 700.16

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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.