If the sin 90° = 1, then which of these statements is true? a. cos 0° = 1, because the cosine and sine are complements. cos 90° = 1, because the cosine and sine are supplements. b. cos 0° = 0, because the cosine and sine are complements. c. cos 90° = 0, because the cosine and sine are supplements.

option 1 is correct.

step-by-step explanation:

given sin 90°=1

we have to choose the correct statement.

as the sine of any acute angle is equal to cosine of its complement i.e these are complements.

sin(90-ф)=cosф and cos(90-ф)=sinф

sin 90°=cos(90-90)°=cos 0°

∴ cos 0°=sin 90°=1

as, sin(180-ф)=sin ф not cos ф

∴ sine and cosine are not supplements

hence, option 1 is correct.

answer: no

step-by-step explanation:

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.