Home / 425.40-637.60-420.84

Finding the Fourth Proportional to 425.40, 637.60 and 420.84

Calculator

Solution

The fourth proportional to 425.40, 637.60 and 420.84 is: 630.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.40 : 637.60 = 420.84 : x
  2. Step 2: Convert to fraction form
    425.40/637.60 = 420.84/x
  3. Step 3: Cross multiply
    425.40x = 637.60 × 420.84
  4. Step 4: Simplify right side
    425.40x = 268,327.58
  5. Step 5: Solve for x
    x = 268,327.58/425.40
  6. Step 6: Final answer
    x = 630.77

Related Problems

Find fourth proportional to 212.70, 318.80 and 210.42
Half scale
Find fourth proportional to 850.80, 1,275.20 and 841.68
Double scale
Find fourth proportional to 426.40, 639.10 and 421.84
Similar ratio
Find fourth proportional to 638.10, 956.40 and 631.26
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.