Maths! (1 Viewer)

[coolboy234]

1. A regular octagon has an area of 500 cm squared. How long to the nearest centimetre is one side of the octagon?

2. Ricky is on an island looking for some treasure. He starts at point X by the palm tree and walks 150m in a direction of 230 degrees north to point Y. He then walks 80m in a direction of 140 degrees north to point Z. At point Z he digs and finds the treasure.
How far in metres is point Z from point X?
(I added the colour to make it more visually exciting, though it may not be.)
http://community.boredofstudies.org/attachment.php?attachmentid=16757&stc=1&d=1216637673

3. A water cooler has cone-shaped paper drinking cups. The volume of a cone can be found using this formula: V = (Pi x radius squared x height) divided by 3
Anton pours water into a cup until it contains water to half of its volume.
What is the depth of the water, to the nearest millimetre, in the cup?
http://community.boredofstudies.org/attachment.php?attachmentid=16758&stc=1&d=1216635986

4. A car follows another car along a straight stretch of an open highway at 100 kilometres per hour. The cars are 150m apart. The cars approach a town. When each car reaches the town it slows down at the same rate to 30 kilometres per hour. Both cars travel through the town at 30 kilometres per hour.
How far apart will the cars be when they are both travelling at 30 kilometres per hour?

 

[ahhliss]

1.
Cut the octagon into 8 isosceles triangles so the area of each triangle is 500/8cm squared.
360/8=45 degrees which is the angle in the middle (can't describe it, hope you get me).
Use area of a triangle to find the equal sides of the triangle by substituting in the area and included angle.
Sine rule with the side you just found to find the side of the octagon.

2.
My diagram ended up with XY and YZ forming a right-angled triangle so just Pythagoras Theorem works according to mine.

3.
Use the information given to find the volume of the cup.
Find half of it and substitute it into the volume formula along with radius.
Rearrange to find height.

If that makes any sense xD I don't have a calculator with me so I couldn't come up with an answer, sorry.

Sorry, I don't get 4. My brain seems to have melted O_O And I'm feeling lazy xD

 

[vds700]

1. A regular octagon has an area of 500 cm squared. How long to the nearest centimetre is one side of the octagon?

2. Ricky is on an island looking for some treasure. He starts at point X by the palm tree and walks 150m in a direction of 230 degrees north to point Y. He then walks 80m in a direction of 140 degrees north to point Z. At point Z he digs and finds the treasure.
How far in metres is point Z from point X?
(I added the colour to make it more visually exciting, though it may not be.)
http://community.boredofstudies.org/attachment.php?attachmentid=16757&stc=1&d=1216637673

3. A water cooler has cone-shaped paper drinking cups. The volume of a cone can be found using this formula: V = (Pi x radius squared x height) divided by 3
Anton pours water into a cup until it contains water to half of its volume.
What is the depth of the water, to the nearest millimetre, in the cup?
http://community.boredofstudies.org/attachment.php?attachmentid=16758&stc=1&d=1216635986

4. A car follows another car along a straight stretch of an open highway at 100 kilometres per hour. The cars are 150m apart. The cars approach a town. When each car reaches the town it slows down at the same rate to 30 kilometres per hour. Both cars travel through the town at 30 kilometres per hour.
How far apart will the cars be when they are both travelling at 30 kilometres per hour?

In future, please dont double post the same Q in more than 1 forum