



 
Hi Summer, I can help get you started. You didn't include a diagram but I expect it looks something like The point $D$ is on the base of the sand castle directly below B so that the angle $NDA$ is a right angle. The length of $BC$ is 20 cm, the length of $BD$ is 30 cm and the length of $AN$ is 34 cm. Since triangle $ABD$ is a right triangle you can use Pythagoras Theorem to find the length of $DA.$ Penny 



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