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Finding the Fourth Proportional to 913.80, 1,261 and 499.80

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Solution

The fourth proportional to 913.80, 1,261 and 499.80 is: 689.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.80 : 1,261 = 499.80 : x
  2. Step 2: Convert to fraction form
    913.80/1,261 = 499.80/x
  3. Step 3: Cross multiply
    913.80x = 1,261 × 499.80
  4. Step 4: Simplify right side
    913.80x = 630,247.80
  5. Step 5: Solve for x
    x = 630,247.80/913.80
  6. Step 6: Final answer
    x = 689.70

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1.5x scale

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.