More Math Help and than I won't bother you anymore!?

Question

A box has a rectangular base of 30cm by 25cm. Iron rods are to be placed in the box.
a.) Calulate the biggest sized rod that could be laid down in the box.
b.) Only one rod is to be placed in the box. Calculate the longest rod possible that can be placed in the box.

Answers:
a.) 39.05
b.) 41.83
But, how do you get thoose answers???

Answer 1

Ok, its a box. We know that the longest side part any rectangle or triangle (if you split the box into two triangles) the longest part will always be the hypotenuse.

The sides of the Box are 25 and 30 cm

Now, we know A^2 + B^2 = C^2

So A can be 25 and B can be 30.....


25^2 + 30^2 = Hypotenuse Squared.

625 + 900 = C^2
Square root of (625+900) = C
C = square root of 1525
C = 39.05124838

Now for the longest rod..... that should be the 39.05124838

But the biggest rod..... should be the 41.83. I think you got your answers fliped.

A. 41.83
B. 39.05

To get answer A. Let me figure that one out, give me time. lolz.

Answer 2

A) The longest rod that will lay flat will go from one corner to the opposite corner. Split the box into two triangles by drawing a diagonal line from one corner to the opposite corner.

Now you have a right-angle triangle to work with and we know that a^2 + b^2 = c^2.

Let one side of the triangle (a) = 30 and the other side (b) = 25.
So we have 30^2 + 25^2 = c^2
Or 900+625=c^2
1525=c^2
39.05=c -- the length of the longest rod that will lay flat.

B) I don't think you can figure this out without knowing the height of the box - the longest rod that will fit in a box isn't one that sits on the bottom.

Answer 3

You omitted the bit that the box was 15cm deep. You have the answer to a) and that is the length of the diagonal of the base now you have to apply pythagorus to that figure and the depth i.e. 39.05^2 + 15^2= 1525+225= 1750 and the sq.root of 1750 = 41.83

Answer 4

if the rod is layed on the diagonal at th bottom of the box, its length would be Sqrt(30^2+25^2) = 39.05 cm.

You do not give the height of the box. If the height were 15cm, then the longest rod would be sqrt(39.05^2+15^2) = 41.83.

Answer 5

The square on the hypotenuse is equal to the sum of the squares on the other two sides.

30² = 900
25² = 625
900+625=1525
The square root of 1525 is 39.05.

Question b) looks the same as question a).

Answer 6

well for a.) split the box in half to make it into 2 triangles to get the distance of this line you use pythagoras theorem (i dont tink i spelt that rite)the hypoteneus squared = 30 squared + 25 squared.
hypot sq=1525
therefore the square root of 1525=39.05

Answer 7

Look for a box with a rectangular base of 30cm by 25cm.
Get some iron rods.
Test them out.
You'll discover the answer within a year.

Answer 8

a) square 30, square 5 and the squares together.

now take the square root of the answer

b) you can't do this without knowing the depth of the box as well

Answer 9

corner to corner 750cm