Question

what is the length of the end of the triangle where the dotted line is
the red line is 45
and the whole blue line is 81
is it 13.5

Answer 1

depends at which point along the blue line the dashed line comes up from.

Answer 2

i dont know if this helps but the longeer blue line to the left is 54

Answer 3

Yeah it's necessary.

I got 15. The little triangle and the big one are kind of similar. All the angle are the same. So all sides are a multiple of the other one. If you see the ratio of the difference between 81 and 54 (which gives the length of the right side of the blue line) against 81... then this is the ratio of the bottom line of that small triangle against the bottom line of the larger triangle... That'll give you the number you need to multiply by to change between the sides of each triangle. Multiplying what by the red line gives the length of the dashed line. I got 15.

Answer 4

yes it is 15 thank u for the detailed explanation