The temperature $T$ of an object in degrees Fahrenheit after $t$ minutes is represented by the equation $T(t)=66 e^{-0.017} 4 t+73$. To the nearest degree, what is the temperature of the object after one and a half hours? ${ }^{\circ} \mathrm{F}$

Step 1 ：The temperature $T$ of an object in degrees Fahrenheit after $t$ minutes is represented by the equation $T(t)=66 e^{-0.017t} +73$.

Step 2 ：We are asked to find the temperature of the object after one and a half hours. Since 1.5 hours is 90 minutes, we substitute $t$ with 90 in the given equation.

Step 3 ：Substituting $t$ with 90, we get $T = 66 e^{-0.017*90} +73$.

Step 4 ：Calculating the above expression, we get $T = 87.29135404285647$.

Step 5 ：Rounding to the nearest degree, we get $T = 87$.

Step 6 ：Final Answer: The temperature of the object after one and a half hours is approximately \(\boxed{87}\) degrees Fahrenheit.