Answer:
$18
Step-by-step explanation:
Given:
6.4x - 2.1x = 77.4
Where,
x = cost of sheet metal per square foot
How much does sheet metal cost per square foot?
6.4x - 2.1x = 77.4
4.3x = 77.4
Divide both sides by 4.3
x = 77.4 / 4.3
= 18
x = $18
Sheet metal per square foot cost $18
<span>By dividing the two numbers we get 104.3495... Rounding this number to two decimal places means that we must keep just 2 digits after the "." symbol, and round the last one of them. In our case, 104.3495... becomes 104.35.</span>
To find the product of a reasonable estimate of two decimal numbers, round each decimals to the nearest whole number and then perform the multiplication.
For example:
3.2 x 5.7
Estimated answer
3.2 will be rounded down to 3 and 5.7 will be rounded up to 6
⇒ 3 x 6 = 18
Actual Answer
3.2 x 5.7
=18.24