Will mark as

peter used black tiles and white tiles to cover a rectangular floor that is 10 feet long by 9 feet wide. each tile is a 6-inch by 6-inch square. if the ratio of white tiles to the total number of tiles is 2: 5, how many white tiles were needed for the floor?

a: 60

b: 36

c: 144

d: 240

A:60

Step-by-step explanation:

9ftx10ft= 90 ft squared = 1080 inches

1080/36 (6x6=36) inches= 30 white tiles x2 because of the ratio

60 white tiles

answer: cos [   arcsin (3/5) - arccos (1/2) ] =

step-by-step explanation: × = 3/5 = 0.6--> x = 36.87 and x = 180 - 36.87 = 143.13 deg

cos y = 1/2 --> y = +- 60 deg a. cos (x - y) = cos (143.13 - 60) = cos 83,13  

=

0.12

b. cos (36.87 - 60) = cos (-23.23) = 0.92