Home / 309.90-464.85-78.80

Finding the Fourth Proportional to 309.90, 464.85 and 78.80

Calculator

Solution

The fourth proportional to 309.90, 464.85 and 78.80 is: 118.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.90 : 464.85 = 78.80 : x
  2. Step 2: Convert to fraction form
    309.90/464.85 = 78.80/x
  3. Step 3: Cross multiply
    309.90x = 464.85 × 78.80
  4. Step 4: Simplify right side
    309.90x = 36,627.86
  5. Step 5: Solve for x
    x = 36,627.86/309.90
  6. Step 6: Final answer
    x = 118.19

Related Problems

Find fourth proportional to 154.95, 232.43 and 39.40
Half scale
Find fourth proportional to 619.81, 929.70 and 157.59
Double scale
Find fourth proportional to 310.90, 466.35 and 79.80
Similar ratio
Find fourth proportional to 464.86, 697.28 and 118.19
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.