Home / 477.20-715.80-421.40

Finding the Fourth Proportional to 477.20, 715.80 and 421.40

Calculator

Solution

The fourth proportional to 477.20, 715.80 and 421.40 is: 632.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    477.20 : 715.80 = 421.40 : x
  2. Step 2: Convert to fraction form
    477.20/715.80 = 421.40/x
  3. Step 3: Cross multiply
    477.20x = 715.80 × 421.40
  4. Step 4: Simplify right side
    477.20x = 301,638.12
  5. Step 5: Solve for x
    x = 301,638.12/477.20
  6. Step 6: Final answer
    x = 632.10

Related Problems

Find fourth proportional to 238.60, 357.90 and 210.70
Half scale
Find fourth proportional to 954.40, 1,431.60 and 842.80
Double scale
Find fourth proportional to 478.20, 717.30 and 422.40
Similar ratio
Find fourth proportional to 715.80, 1,073.70 and 632.10
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.