Home / 415.40-623.10-391.40

Finding the Fourth Proportional to 415.40, 623.10 and 391.40

Calculator

Solution

The fourth proportional to 415.40, 623.10 and 391.40 is: 587.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.40 : 623.10 = 391.40 : x
  2. Step 2: Convert to fraction form
    415.40/623.10 = 391.40/x
  3. Step 3: Cross multiply
    415.40x = 623.10 × 391.40
  4. Step 4: Simplify right side
    415.40x = 243,881.34
  5. Step 5: Solve for x
    x = 243,881.34/415.40
  6. Step 6: Final answer
    x = 587.10

Related Problems

Find fourth proportional to 207.70, 311.55 and 195.70
Half scale
Find fourth proportional to 830.80, 1,246.20 and 782.80
Double scale
Find fourth proportional to 416.40, 624.60 and 392.40
Similar ratio
Find fourth proportional to 623.10, 934.65 and 587.10
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.