You may have thought that because 8 is 2 more than 6, JB would be 2 more than 5. However, in similar triangles, side lengths are proportional. $\displaystyle{\overline{{{T}{L}}}}\usepackage{cmbright}\Huge\$ corresponds to $\displaystyle{\overline{{{J}{B}}}}\usepackage{cmbright}\Huge\$ , and $\displaystyle{\overline{{{B}{T}}}}\usepackage{cmbright}\Huge\$ corresponds to $\displaystyle{\overline{{{P}{J}}}}\usepackage{cmbright}\Huge\$ . Now set up the correct proportion and solve.