If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains ***.kastatic.org** and ***.kasandbox.org** are unblocked.

Main content

Current time:0:00Total duration:2:04

use these semicircles and a semi-circle semi means semi means half so use these half circles to make a circle so if you take two halves of a circle if you put them together just right you're going to make a circle so how do we do that well this first choice right over here these are no longer the semi circles these are each a third of a circle so we're not going to this isn't and this doesn't even complete the entire circle so that didn't make a circle this one they took the two semi circles but they didn't make them so that their outsides completely line up with each other so this isn't a circle but this one they took the two semi circles and they put them together just right so now their outsides line up and we have a full circle so that's our choice and we got it right let's keep doing this use these small triangles to make a big triangle all right well here they use them to make not a triangle but this looks like a parallelogram a quadrilateral here they've used the two triangles and they've made a triangle because this whole thing has three sides one two three here they use those two triangles to make a square but we want to make a big triangle so this is our choice let's do a few more of these use these semi circles to make a circle well here they're not meeting on the flat side so this isn't this isn't a circle this is looks like something else like two smiles or something two pieces of a blue watermelon slice on top of a purple one this is a circle so that they the two semicircles in the right way and here they didn't even make the meet so this would be our choice use these small rectangles to make a big rectangle well here they didn't line them up right to make a big rectangle here they did this whole thing has one two three four sides so I'll click that one this one doesn't look like a rectangle looks like some type of an L or something so I'm not going to select that one and we got it right