Answer:
The length of the longest side of the triangle is 21 inches.
Explanation:
Sum of ratios = 5 + 7 + 2
= 14
First side of the triangle =
×

= 5 × 3
= 15 inches
2nd side of the triangle =

= 7 * 3
= 21 inches
3rd side of the triangle =

= 2 × 3
= 6 inches
∴The longest side of the triangle is 21 inches.
Hope this helps