Math Folks Inside Please

[Good Ol' Boy]

I know basic math, I work with it every day. But not so great on stuff I'm not familiar with.

So my regular steel target that I practice with is a 66% IDPA target. What I would like to know is if I'm drilling at say 12yds, what is the actual distance of my target if it were a standard size IDPA cardboard target.

I'm "thinking" if I take the difference of 66, which is 34, and times that by the distance I'm shooting at, let's say 12yds, then add that number to 12yds it would be close to what the distance would be for a fullsize target.

Like I said I'm not good with math like this so some help would be appreciated.

 

[Good Ol' Boy]

ETA, if I take 12yds and multiply it by 66% I get 7.92. If I then add that to the 12yds it comes out to almost 20 yds.

So shooting at 12yds at my 66% target is basically like shooting at about 20yds at a fullsize target.

Does that sound right?

 

[earlthegoat2]

I think it would be 18 yds.

66% is about 2/3.

2/3 of 18 is 12.

 

[WrongHanded]

I don't know what the 66% refers to, but I assume it means the target you have is 66% the size of a true IDPA target?

If that's true, divide the distance to your target by 66, then multiply by 100.

12 ÷ 66 = 0.1818
0.1818 × 100 = 18.18

Or more simply, 66% is almost 2/3rds. So divide the actual distance by 2 and multiply by 3, to get the theoretical distance.

12 ÷ 2 = 6
6 × 3 = 18

Or to streamline even more, 1 ÷ 2 = 0.5 ; and 0.5 × 3 = 1.5.
So just multiply the actual distance by 1.5, to get your theoretical distance.

12 × 1.5 = 18

 

[Good Ol' Boy]

I think it would be 18 yds.

66% is about 2/3.

2/3 of 18 is 12.

I'm not discounting you but none of that makes sense. When I use my fraction calculator 18 divided by by 2/3 is 27.

 

[Sistema1927]

I'm not discounting you but none of that makes sense. When I use my fraction calculator 18 divided by by 2/3 is 27.

Try 18 "times" 2/3. You are going about it all backwards.

 

[Good Ol' Boy]

I don't know what the 66% refers to, but I assume it means the target you have is 66% the size of a true IDPA target?

If that's true, divide the distance to your target by 66, then multiply by 100.

12 ÷ 66 = 0.1818
0.1818 × 100 = 18.18

Or more simply, 66% is almost 2/3rds. So divide the actual distance by 2 and multiply by 3, to get the theoretical distance.

12 ÷ 2 = 6
6 × 3 = 18

Or to streamline even more, 1 ÷ 2 = 0.5 ; and 0.5 × 3 = 1.5.
So just multiply the actual distance by 1.5, to get your theoretical distance.

12 × 1.5 = 18

You're absolutely right in your assumptions about the target size and distance.

I just don't understand where you're coming up with the math.

 

[Good Ol' Boy]

Try 18 "times" 2/3. You are going about it all backwards.

Ok, but then how does the 12 calculate into the already 12yds?

 

[Legionnaire]

Think of it this way. If the target is 66% of a full sized target, it appears full size at 66% of the distance. Just divide your actual distance by 0.66. If it's actually "2/3" and not 66%, divide by 0.6666.

Thus, a 50% target at 20 yards would look the same as a full sized target at 20/0.50 or 40 yards, and your 66% target at 12 yards will look the same as a full sized target at 12/.66 or 18.18 yards.

 

[Nuclear]

12/0.66=x/1

x=18

So if you are shooting a 2/3 (0.66) sized target a 12 yards, it is the equivalent to shooting a full sized target at 18 yards.

 

[hso]

Hint - draw a triangle

 

[Pudge]

Ok, but then how does the 12 calculate into the already 12yds?

Divide the distance by .66 (66%).

 

[WrongHanded]

You're absolutely right in your assumptions about the target size and distance.

I just don't understand where you're coming up with the math.

The first is percentages. The second is fractions. The third is the simplest approximation.

Get a tape measure and lay it on the floor stretched to 100 inches. Put a marker at 66 inches, and go stand at zero. The marker at 66 is where your target actually is. But it looks like it's at 100.

The same thing is true for feet, or yards. When the target is at 66, it looks like it's at 100.

 

[Good Ol' Boy]

Think of it this way. If the target is 66% of a full sized target, it appears full size at 66% of the distance. Just divide your actual distance by 0.66. If it's actually "2/3" and not 66%, divide by 0.6666.

Thus, a 50% target at 20 yards would look the same as a full sized target at 20/0.50 or 40 yards, and your 66% target at 12 yards will look the same as a full sized target at 12/.66 or 18.18 yards.

That I understand, and works out on my calculator.

 

[Good Ol' Boy]

Thanks everyone for the help.

 

[lysanderxiii]

IDPA target = X inches
Your target = X inches x .66
IDPA Range = Y yards (Y x 36 inches)
Your range = 12 yards (12 x 36 inches = 432 inches)
2φ = your dispersion angle

tan φ = [X (.66)] / [2 (432)]

tan φ = X / [2 (Y)]

[X (.66)] / [2 (432)] = X / [2 (Y)]

X / 1309.091 = X / [2 (Y)]

The "Xs" cancel

So, Y = 645.545 inches, or 18.182 yards

 

[codytrucker]

whatever range you set your target at , divide by 2 ( or 1/2 , or .5 ) add that number back to your range and you'll always get the full size range.

 

[BreechFace]

The distance you are shooting at 12 yards * 3/2 = 18 yards

Multiply your shooting distance by the inverse fraction of your IDPA reduced target.

12 x 3 = 36 = 18
1 .x. 2 .=. 2 .=. 1

Disregard the “.” they are just spacers to get the fractions to line up.

 

[LiveLife]

66% = 12 yards
100% X yards

So 66 times X = 100 times 12
and X = 1200 divided by 66

X ~ 18 yards

 

[doubleh]

Without any complicated math and doing it in my mine it's easy. 66% is basically two thirds of the size of the regular target. You are shooting at 12 yards so divide 12 by 2 and get 6. Add 6 to 12 and you have a whole which is 18 yards. It took a lot longer to type this than to do the math. The slight difference of the 2/3% not used won't be noticed on your target.

 

[Rule3]

How many replies doe it take to get to 18? (1st reply)

This is getting confusing!

 

[Col. Harrumph]

I guess Lysander is an engineer; that's how an engineer (or a mathematician) would approach the problem. The rest of us are approximators, which is the next best thing.

 

[BreechFace]

How many replies doe it take to get to 18? (1st reply)

This is getting confusing!

While Post #3 is correct it comes at it from knowing the answer and working back. I tried to simplify it (post #18) by knowing the known distance one is shooting at and finding the answer of what the 2/3 IDPA target simulates.

But it seems we have some people who's love language is math (speaking at you @lysanderxiii), which is great we are gifted differently. Not trying to belittle @lysanderxiii just was like "wow".

But to the point @lysanderxiii is 0.182 yards more correct than me. Engineers they have a more correct answer for everything.

 

[ojh]

x is the unknown distance
12 is the known distance
66% is the relative size of the reduced target
100% is the relative size of the full-size target
The ratio of distances is equal with the ratio of relative target sizes.
x / 12 = 100 / 66
x = (100 / 66) * 12
x ≈ 18.2

 

[Rule3]

While Post #3 is correct it comes at it from knowing the answer and working back. I tried to simplify it (post #18) by knowing the known distance one is shooting at and finding the answer of what the 2/3 IDPA target simulates.

But it seems we have some people who's love language is math (speaking at you @lysanderxiii), which is great we are gifted differently. Not trying to belittle @lysanderxiii just was like "wow".

But to the point @lysanderxiii is 0.182 yards more correct than me. Engineers they have a more correct answer for everything.

I am still till trying to find out what a 66% IDPA target is.

https://www.midwayusa.com/product/939467980?pid=777756