Cycloalkene which exhibits geometrical isomerism is
Generally in lower cycloalkenes geometrical isomerism cannot be observed at double bond site as trans isomer is not possible due to highly strained conditions. But in higher cycloalkenes it can be observed
Cyclooctene is the smallest ring that can show both cis and trans isomers because it is flexible enough to twist into the trans conformation. The cis and trans isomers of cyclooctene are shown above.