Find the number of permutations of the word \"helicopter.\". a.3,628,800. b.1,814,400. c.328,800. d.452.

Ineed with number 17 i don’t get it at alll

The radius of the circle is 4 cm and the measure of the central angle is 90° the area of the sector with a central angle measuring 90° and radius of length 4 cm is vt cm the triangle in the sector is 4 cm the area of the triangle is v/cm² the area of the segment of the circle is (471 - ) cm?

Icould really use some with this question.