Can't they use a ladder?

If your leg has a mass of 2kg, 1.1×10^10 J of kinetic energy would require your leg to be moving at about 150 km/second not faster than the speed of light.

TLDR: Their math is shit.

I wanted a least squares solution, but all I got were these right triangles!

Thats inefficient, you dont need to cancel the angular momentum as there was no time limit on how long it takes rhe child to enter the sun and there also was not a specified required trajectory. The child can just spiral into the sun

or

heavier foot

tape + brick

Surely they're not so mad that they need to kick their child into the sun. I'm sure a low solar orbit would suffice.

Why does it have to be a kick? Could I generate that force with a car? It weighs a lot more so I assume the speed wouldn't need to be nearly as high.

Cut the extra inch off the long side to get a 4" square, then cut the remaining 1" x 4" piece into 4 1" squares. The boy never said the squares had to be the same size.

If the triangles have already been cut, it's a peanut butter sandwich: use peanut butter on the edges to glue it back together and cut the squares. The child gave you a challenge, think outside the box!

I was really hoping he was going to convert the amount of energy needed into calories, then from calories into peanuts butter sandwiches