The diagram can be thought of as a right triangle with a hypotenuse of 8m, and a base of 1.4m. We can solve for the vertical height by using Pythagorean theorem.

Substitute the following given to the Pythagorean theorem and we have
![\begin{gathered} a^2+b^2=c^2 \\ a^2+(1.4\text{ m})^2=(8\text{ m})^2 \\ a^2+1.96\text{ m}^2=64\text{ m}^2 \\ a^2=64\text{ m}^2-1.96\text{ m}^2 \\ a^2=62.04\text{ m}^2 \\ \sqrt[]{a^2}=\sqrt[]{62.04\text{ m}^2} \\ a=7.8765474670060866713113634659718\text{ m} \\ a\approx7.9\text{ m} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/86zk6pcfppeyhdj83lqudct90igx9ygvie.png)
Therefore, it is 7.9 m high up the wall where the top of the ladder reach.