How do i figure out 3/4 of 640 fraction

Write the expression in standard form 4 (2a) + 7 (-4b) + (3*c*5).

A spruce tree is approximately the shape of a cone with a slant height of 20 ft. The angle formed by the tree with the ground measures 72º. Estimate the height of the tree. Round to the nearest foot.

In a well-written paragraph, explain whether you believe the Electoral College should be abolished. Make sure to justify your position with at least three

ABC Computers sold 30 tablets this week. Their goal is to sell at least 33% more next week. Graph an inequality that represents their goal.

Olga purchases a rectangular mirror (the shaded region) that fits exactly inside a frame. The outer perimeter of the frame measures 60 cm by 80 cm. The width of each side of the frame is 10 cm. What is the area of the mirror?

A newspaper reporter wants to know how popular the hobby of bird watching is in the city. He asked people at the local bird refuge if they watched birds as a hobby. Which of the following best explains whether the reporters data is valid or not?

I am very confused on how to figure out if y = 3/4x is proportional?

Alison wants to buy a mountain bike for $339.12. If she saves $28.26 each month, in how many months will she be able to buy the bike?

At 12 o'clock the temperature was 7°C. The temperature decreased by - 20°C. What is the new temperature?

Ashleys rentals charges $27.50 per hour to rent a surfboard and a wetsuit. Darlas surf shop charges $23.25 per hour to rent a surfboard plus $17 extra for a wetsuit.