Home / 99.70-148.73-85.90

Finding the Fourth Proportional to 99.70, 148.73 and 85.90

Calculator

Solution

The fourth proportional to 99.70, 148.73 and 85.90 is: 128.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.70 : 148.73 = 85.90 : x
  2. Step 2: Convert to fraction form
    99.70/148.73 = 85.90/x
  3. Step 3: Cross multiply
    99.70x = 148.73 × 85.90
  4. Step 4: Simplify right side
    99.70x = 12,775.91
  5. Step 5: Solve for x
    x = 12,775.91/99.70
  6. Step 6: Final answer
    x = 128.14

Related Problems

Find fourth proportional to 49.85, 74.37 and 42.95
Half scale
Find fourth proportional to 199.40, 297.46 and 171.80
Double scale
Find fourth proportional to 100.70, 150.22 and 86.90
Similar ratio
Find fourth proportional to 149.55, 223.10 and 128.85
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.