Arithmetic sequences

9000064801

Level: 
C
The sides of a right triangle form three consecutive terms of an arithmetic sequence. The perimeter of the triangle is \(60\, \mathrm{cm}\). Find the hypotenuse of the triangle (the longest side).
\(25\, \mathrm{cm}\)
\(12\, \mathrm{cm}\)
\(15\, \mathrm{cm}\)
\(20\, \mathrm{cm}\)
\(30\, \mathrm{cm}\)

9000064805

Level: 
C
The sides of a box form three consecutive terms of an arithmetic sequence. The volume of the box is \(665\, \mathrm{cm}^{3}\). The shortest side is \(5\, \mathrm{cm}\). Find the surface area of the box.
\(501\, \mathrm{cm}^{2}\)
\(315\, \mathrm{cm}^{2}\)
\(615\, \mathrm{cm}^{2}\)
\(805\, \mathrm{cm}^{2}\)
\(1\: 215\, \mathrm{cm}^{2}\)