Home / 429.09-643.70-140.50

Finding the Fourth Proportional to 429.09, 643.70 and 140.50

Calculator

Solution

The fourth proportional to 429.09, 643.70 and 140.50 is: 210.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.09 : 643.70 = 140.50 : x
  2. Step 2: Convert to fraction form
    429.09/643.70 = 140.50/x
  3. Step 3: Cross multiply
    429.09x = 643.70 × 140.50
  4. Step 4: Simplify right side
    429.09x = 90,439.85
  5. Step 5: Solve for x
    x = 90,439.85/429.09
  6. Step 6: Final answer
    x = 210.77

Related Problems

Find fourth proportional to 214.55, 321.85 and 70.25
Half scale
Find fourth proportional to 858.18, 1,287.40 and 281
Double scale
Find fourth proportional to 430.09, 645.20 and 141.50
Similar ratio
Find fourth proportional to 643.64, 965.55 and 210.75
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.