Given:
In triangle [tex]FJH,KG\parallel JH, FK=3, KJ=15,\text{ and }FG=4.[/tex]
To find:
The length of [tex]FH[/tex].
Solution:
Basic proportionality theorem(BPT): If a line intersect the two sides of a triangle and parallel to third side of the triangle, then it divides the sides proportionally.
In triangle [tex]FJH,KG\parallel JH[/tex].
Using BPT, we get
[tex]\dfrac{FK}{KJ}=\dfrac{FG}{GH}[/tex]
[tex]\dfrac{3}{15}=\dfrac{4}{GH}[/tex]
On cross multiplication, we get
[tex]3\times GH=4\times 15[/tex]
[tex]GH=\dfrac{60}{3}[/tex]
[tex]GH=20[/tex]
Now,
[tex]FH=FG+GH[/tex]
[tex]FH=4+20[/tex]
[tex]FH=24[/tex]
Therefore, the length of FH is 24 units.
