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Finding the Fourth Proportional to 1,085.40, 1,628.10 and 915.30

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Solution

The fourth proportional to 1,085.40, 1,628.10 and 915.30 is: 1,372.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,085.40 : 1,628.10 = 915.30 : x
  2. Step 2: Convert to fraction form
    1,085.40/1,628.10 = 915.30/x
  3. Step 3: Cross multiply
    1,085.40x = 1,628.10 × 915.30
  4. Step 4: Simplify right side
    1,085.40x = 1,490,199.93
  5. Step 5: Solve for x
    x = 1,490,199.93/1,085.40
  6. Step 6: Final answer
    x = 1,372.95

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.