The given ratio of the sides of the triangles is 4:10:7. Let the sides be 4x, 10x and 7x .
And given perimeter is 252 meters .
Perimeter is the sum of all sides. So we get

Dividing both sides by 21

So the sides are

2730/10,000 in decimal notation is 0.273
She is incorrect, the product will have 3 decimal places.
<span>2d – e = 7 </span>
<span>d + e = 5 </span>
<span>3d=12 </span>
<span>d=4 </span>