Answer:
The sum of the measures of the interior angles of a regular polygon if each exterior angle measures 72° is 540°.
Explanation:
The formula to find the measure of each exterior angle of a regular polygon is
![Exterior=(360)/(n)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9sch8y9gjoaxqkah5hqy6wxl5ku8j10slb.png)
It is given that the measure of each exterior angle of a regular polygon is 72°.
![72=(360)/(n)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/i6vmagjtqxs9rl12bguzt4qk3juuk8z24x.png)
Multiply both sides by n.
![72n=360](https://img.qammunity.org/2020/formulas/mathematics/middle-school/pi0sqwfnivf38w06wutyj6yts52u2nz8c4.png)
Divide both sides by 72.
![n=(360)/(72)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/86lfmngnb9abdn8d7zm3clx0myrcgch782.png)
![n=5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2d2jdmq7o6tn3nz9ok48m1pfvfg58a04nx.png)
It means the number of vertices of the polygon is 5. It means the given polygon is pentagon.
The sum of interior angles of a regular polygon is
![Sum=(n-2)* 180](https://img.qammunity.org/2020/formulas/mathematics/middle-school/y975xaznjikwys4sje900rrcwpb422hf5h.png)
Substitute n=5.
![Sum=(5-2)* 180](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yow8d8b7tmr2swh4hfj8mdaqskoym8qa39.png)
![Sum=3* 180](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ku7gp8pgmidxcm72bobz29bryxwvjuwe8t.png)
![Sum=540](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ltjai9nu4de5syvpimemxgmapr2qiti48a.png)
Therefore the sum of the measures of the interior angles of a regular polygon if each exterior angle measures 72° is 540°.