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Finding the Fourth Proportional to 644.75, 890.15 and 424.05

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Solution

The fourth proportional to 644.75, 890.15 and 424.05 is: 585.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.75 : 890.15 = 424.05 : x
  2. Step 2: Convert to fraction form
    644.75/890.15 = 424.05/x
  3. Step 3: Cross multiply
    644.75x = 890.15 × 424.05
  4. Step 4: Simplify right side
    644.75x = 377,468.11
  5. Step 5: Solve for x
    x = 377,468.11/644.75
  6. Step 6: Final answer
    x = 585.45

Related Problems

Find fourth proportional to 322.38, 445.08 and 212.03
Half scale
Find fourth proportional to 1,289.50, 1,780.30 and 848.10
Double scale
Find fourth proportional to 645.75, 891.53 and 425.05
Similar ratio
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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.