2. what do we call the little lines that divide number lines into equal parts?

Step-by-step explanation:

A number line can be defined as a straight line with numbers placed at equal intervals. A number line can be extended infinitely in any direction and is usually represented horizontally. It can be used to represent both positive and negative integers. Every number on the number line  has an absolute value, which simply means how far that number is from zero. The section of the number line between two numbers is called an interval. The distance between a number's place on the number line and 0 is called the number's absolute value..

answer: i don't understand it

step-by-step explanation: sorry

< xcy ≅ < xby

step-by-step explanation:

in δcax and δbax,

so, δcax ≅ δbax (side-angle-side or sas)

since δcax ≅ δbax, we can conclude < acx ≅ < abx

in δacy and δaby,

so, δacy ≅ δaby (side-angle-side or sas)

since δacy ≅ δaby, we can conclude < acy ≅ < aby

now,

< acy ≅ < aby

=> < acx + < xcy ≅ < abx + < xby

=> < acx + < xcy ≅ < acx + < xby   (since < acx ≅ < abx already proved above)

subtracting < acx from both sides, we get

< acx + < xcy -< acx ≅ < acx + < xby -< acx

cancelling out < acx and -< acx from both sides, we get

< xcy ≅ < xby (proved)