capnrefsmmat/khan-exercises — comment on commit dcf76a0258e3fe66a6a802eb85dc5ab800815227
File: exercises/dot_products.html line 51
By smenks13:

I would then stick a hint after this one to "dummy-proof" the problem like so:
```

= AX * BX + AY * BY

= AX * BX + AY * BY

```
Just so someone who's completely lost can still type in the given answer and get credit.