Home / 666.90-920.16-397.71

Finding the Fourth Proportional to 666.90, 920.16 and 397.71

Calculator

Solution

The fourth proportional to 666.90, 920.16 and 397.71 is: 548.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.90 : 920.16 = 397.71 : x
  2. Step 2: Convert to fraction form
    666.90/920.16 = 397.71/x
  3. Step 3: Cross multiply
    666.90x = 920.16 × 397.71
  4. Step 4: Simplify right side
    666.90x = 365,956.83
  5. Step 5: Solve for x
    x = 365,956.83/666.90
  6. Step 6: Final answer
    x = 548.74

Related Problems

Find fourth proportional to 333.45, 460.08 and 198.86
Half scale
Find fourth proportional to 1,333.80, 1,840.32 and 795.42
Double scale
Find fourth proportional to 667.90, 921.54 and 398.71
Similar ratio
Find fourth proportional to 1,000.35, 1,380.24 and 596.57
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.