Find the height of a door on a scale drawing if the door is 2 meters tall and the scale is 1 centimeter = 4 meters

The book and disk company sells its books for $3.00 profit and its disks for a $4.00 profit. the company needs at least 1000 books and discs total and at most 700 books and 400 disks. its profit is shown by the equation profit=3b+4d

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

Which statement justifies why angle ebc measures 90?