A regular triangular pyramid has a base and lateral faces that are congruent equilateral triangles. It has a lateral surface area of 63 square centimeters. What is the surface area of the regular triangular pyramid?

What is the number 321,000,000 in scientific notation? also what is the number? ?

Koji is installing a rectangular window in an office building. the window is 823 feet wide and 534 feet high. the formula for the area of a rectangle is a=bh. what is the area of the window? enter your answer as a mixed number in simplest form in the box. $$ ft2

50 points~ ! i have to turn this in tomarrow