Home / 155.90-215.07-90.39

Finding the Fourth Proportional to 155.90, 215.07 and 90.39

Calculator

Solution

The fourth proportional to 155.90, 215.07 and 90.39 is: 124.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.90 : 215.07 = 90.39 : x
  2. Step 2: Convert to fraction form
    155.90/215.07 = 90.39/x
  3. Step 3: Cross multiply
    155.90x = 215.07 × 90.39
  4. Step 4: Simplify right side
    155.90x = 19,440.64
  5. Step 5: Solve for x
    x = 19,440.64/155.90
  6. Step 6: Final answer
    x = 124.70

Related Problems

Find fourth proportional to 77.95, 107.53 and 45.20
Half scale
Find fourth proportional to 311.81, 430.13 and 180.79
Double scale
Find fourth proportional to 156.90, 216.45 and 91.39
Similar ratio
Find fourth proportional to 233.85, 322.60 and 135.59
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.