For number 3 I believe the answer is A\
Watt is used to measure electricity. Fahrenheit is mostly used in the US for temp. Celsius is used everywhere else for temp. And C and kelvin are used scientifically for temp :)
I guess you need solution on C++. Here is the code:
int main () { double areaofsquare; double length cin >> areaofsquare;
<span>length = sqrt(areaOfSquare);
std::cout << length << std::endl;</span> if(areaofsquare >= 0) { sqrt(areaofsquare); cout << areaofsquare << endl; } else { cout << "INVALID" << endl; }
}
