This is a cone, we know the H and S. Because there is a triangle inside, so we can use  to get the radius. And then, we only need to put the number in the equation to get the answer.

This week, we’ve learned the rational exponents.

This week, we’ve learned about the exponents, this is a question above the negative exponents and the exponent law.

 This week, we learned entire radicals and mixed radicals. in lesson#6, I have learnt an important formula for triangle, that is c²=a²+b².