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Finding the Fourth Proportional to 787.51, 1,085.83 and 645.24

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Solution

The fourth proportional to 787.51, 1,085.83 and 645.24 is: 889.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.51 : 1,085.83 = 645.24 : x
  2. Step 2: Convert to fraction form
    787.51/1,085.83 = 645.24/x
  3. Step 3: Cross multiply
    787.51x = 1,085.83 × 645.24
  4. Step 4: Simplify right side
    787.51x = 700,622.17
  5. Step 5: Solve for x
    x = 700,622.17/787.51
  6. Step 6: Final answer
    x = 889.67

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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.