Answer:
The length of the segment AB is 18.8 cm or 1.88 dm
Explanation:
The question in English is
Points A, B and C are collinear in this order. Find the length of the segment: a) AB, if AC = 20 cm, BC = 0.12 dm
we have that
----> by Addition segment postulate
substitute the given values in centimeters
Remember that
![1\ dm=10\ cm](https://img.qammunity.org/2021/formulas/mathematics/high-school/r915y1q68pe3kr7yfllt1wnu2n6f7161et.png)
so
![0.12\ dm=0.12(10)=1.2\ cm](https://img.qammunity.org/2021/formulas/mathematics/high-school/1yk47ho98zqqle63wf1qzpvnufle3pn963.png)
![20=AB+1.2](https://img.qammunity.org/2021/formulas/mathematics/high-school/tesl0i0g24ad5bcobjmg4avryydmpurx5u.png)
solve for AB
![AB=20-1.2\\AB=18.8\ cm](https://img.qammunity.org/2021/formulas/mathematics/high-school/xvrrhrkmwe4crd5sunqbfs2qacbtra1z0p.png)
Convert to dm
![18.8\ cm=18.8/10=1.88\ dm](https://img.qammunity.org/2021/formulas/mathematics/high-school/zktv09smd3jo1m5zypooexszv0g7izjixy.png)
therefore
The length of the segment AB is 18.8 cm or 1.88 dm