What is 81 percent as a letter grade?

What has five faces of which four faces are triangles and one face is a square all triangular faces meet at one point? True or false Because they have no dimension two points that are very close together will never overlap? How do you write 19 207 485 000 000 in words? Round 12.0087 to decimal places? What is an eighteen sided shape? How many times is the word 'prepare' used in the bible? What number multiplied by itself gives the answer 12345678987654321? Why do you need the Pythagorean theorem? 7000 mm equals how many m? What are the steps for writing a number using scientific notation? How do you add two or more vectors? Is the square root of 225 rational? What are examples of a natural number? How long will it take to travel 27 miles going 2 mph? How many tens are in 643? What are the common factor of 125 and 400? Does the plus sign form 2 pairs of congruent angles? What is half of 189.08? What are the ways to evaluate learning? What is 3 times as much as 40?