we have

Group terms that contain the same variable, and move the constant to the opposite side of the equation

Factor the leading coefficient

Complete the square. Remember to balance the equation by adding the same constants to each side


Rewrite as perfect squares

-----> equation in vertex form
therefore
the answer is the option C

When height turns to 3 times height or 3h
we can replace h with 3h and see what happens
A=1/2b(3h)
A=3/2bh
A=3(1/2bh)
well, the area is trippled
39/100 is the simplest form
Answer: 
Step-by-step explanation:
Substitute the value of the radius of the Earth into the formula given in the problem, where r is the radius, to obtain the surface area of the Earth:

The problem says that the dry land forms 29.2% of the Earth’s surface, therefore, multiply the surface area by 
Threfore, the area of dry land is the following:
