Home / 918.72-1,376.86-430.90

Finding the Fourth Proportional to 918.72, 1,376.86 and 430.90

Calculator

Solution

The fourth proportional to 918.72, 1,376.86 and 430.90 is: 645.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.72 : 1,376.86 = 430.90 : x
  2. Step 2: Convert to fraction form
    918.72/1,376.86 = 430.90/x
  3. Step 3: Cross multiply
    918.72x = 1,376.86 × 430.90
  4. Step 4: Simplify right side
    918.72x = 593,288.97
  5. Step 5: Solve for x
    x = 593,288.97/918.72
  6. Step 6: Final answer
    x = 645.78

Related Problems

Find fourth proportional to 459.36, 688.43 and 215.45
Half scale
Find fourth proportional to 1,837.44, 2,753.72 and 861.80
Double scale
Find fourth proportional to 919.72, 1,378.36 and 431.90
Similar ratio
Find fourth proportional to 1,378.08, 2,065.29 and 646.35
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.