1.the area of a stage in square shape is 676 m2.find its len

1.the area of a stage in square shape is 676 m2.find its length.
2.dad gives a box of candies to mandy for her birthday.the box is a cuboid which has length 10cm ,width 6cm and volume 180cm.find its height.
3.jack uses a piece of wire to from an equilateral triangle of side 14cm.but michelle reforms it to be a square.what is the area of the square?
4.francis had $150.he used 20% of the amount to buy stationery and 34% to buy a toy.
a.how much did he save he leave?
b.if franic saved 50% of the remainder,how munch did he save?
5.miss chueng asked her students to calculate 18.84×31.27and correct the answer to the nearest ten.joe,ken and eva proposd three different calculation methods.try to complete the following.
a.joe:calculate 18.84×31.27=___________
joe's answer was___________(correct to the nearest ten)
b.ken:write doen 18.84=___________(correct to nearest one)
31.27=___________(correct to nearest one)
multiply the two approximate values_________×_________=_________
ken's answer was________(correct to the ten)
c.eva:write dowen 18.84=________(correct to the ten)
31.27=________(correct to the ten)
multiply the two approximate values_________×_________=_________
eva's answer was________(correct to the ten)
6.according to question 5 whose method is the best?_________