Andrea notices that the 40-foot tree next to her is casting a 10-foot shadow. how tall, in inches, is andrea if she is casting a 15-inch shadow at the same time?

If andrea sees that a 40-foot tree casts a 10-foot shadow then, the problem   used for that was 40 divided by 10, which was 4. now we do a reverse problem since we know the shadow casted was 15inches, we multiply 4. 15 multiplied by 4 is 90.the answer is 90 inches.