Here we have one large triangle with two smaller triangles drawn inside. The two smaller triangles are similar.
Thus, a/12 = 12/16, or a/12 = 3/4, or 4a=36, or a = 9.
Find b in the same way: b/20 = 9/12 (and so on).
She has to 40 more laps. 50% is a half, so 40 is half of something. so you are dividing 40 by a half, which is 80. half of 80 is 40.
What you need to do is make each fraction into a decimal and then put them in order from least to greatest.
7/12=0.583
1/8= 0.125
5/16= 0.3125
5/6= 0.83
The order for this is 0.3125, 0.125, 0.583, and 0.83. So the answer is last option
You can do 5 x 1\6 using 5 models and shading in 1\6 per model