First add the number of feet together and then add the number of inches.
2 feet + 4 feet + 3 feet = 9 feet.
\(2\frac{\mathrm{1} }{\mathrm{2}}\)in + \(3\frac{\mathrm{3} }{\mathrm{8}}\)in + \(9\frac{\mathrm{3} }{\mathrm{4}}\)in = \(\frac{\mathrm{5} }{\mathrm{2}}\) + \(\frac{\mathrm{27} }{\mathrm{8}}\) + \(\frac{\mathrm{39} }{\mathrm{4}}\) = \(\frac{\mathrm{20} }{\mathrm{8}}\) +\(\frac{\mathrm{27} }{\mathrm{8}}\) + \(\frac{\mathrm{78} }{\mathrm{8}}\) = \(\frac{\mathrm{125} }{\mathrm{8}}\) = \(15\frac{\mathrm{5} }{\mathrm{8}}\)in
\(15\frac{\mathrm{5} }{\mathrm{8}}\)in = 1ft \(3\frac{\mathrm{5} }{\mathrm{8}}\), so altogether 9ft + 1ft \(3\frac{\mathrm{5} }{\mathrm{8}}\)iin =10 ft \(3\frac{\mathrm{5} }{\mathrm{8}}\)in.