Complete the number patterns

1. 1,3,6,10,15,

2. 1,3,7,13,21,

Write 17/20 as a decimal and as a percent.

Based on the graph, what is the initial value of the linear relationship? a coordinate plane is shown. a line passes through the y-axis at -2 and the x-axis at 3.

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'