The Decisive Battle at Last! is the 229th chapter of the Dragon Ball manga.
The cover of this chapter shows Goku and Gohan riding a dinosaur. The title of the series is spelled wrong, being written Dagon Ball (with the R missing) instead of Dragon Ball. The cover art for this chapter is also featured in the Akira Toriyama - The World artbooks.
Vegeta shows Goku the power of a Saiyan elite, shaking the whole planet with his great power. Their battle resumes with Vegeta easily gaining an upperhand over Goku, even though Goku is using Kaio-ken x2. With no other options on how to defeat Vegeta, Goku decides he must power up to Kaio-ken x3.