Question

Which expression is equivalent to $4.4\times {10}^5{\text{cm}}^2+7.5\times {10}^4{\text{cm}}^2$?

• A. $4.15\times {10}^5{\text{cm}}^2$
• B. $5.15\times {10}^4{\text{cm}}^2$
• C. $4.15\times {10}^4{\text{cm}}^2$
• D. $5.15\times {10}^5{\text{cm}}^2$

Answer 1

The correct option is D $5.15\times {10}^5{\text{cm}}^2$

Given expression: $4.4\times {10}^5{\text{cm}}^2+7.5\times {10}^4{\text{cm}}^2$

To add two values with different exponents, make the exponents have the values same.

$44\times {10}^4+7.5\times {10}^4$

$=(44+7.5)\times {10}^4$

$=51.5\times {10}^4{\text{cm}}^2$

$=5.15\times {10}^5{\text{cm}}^2$