Suppose $Z$ follows the standard normal distribution. Use the calculator provided, or this table, to determine the value of $c$ so that the following is true.
\[
P(Z> c)=0.8907
\]
Round your answer to two decimal places.

Step 1 ：Suppose $Z$ follows the standard normal distribution. We need to determine the value of $c$ so that the following is true: \[P(Z>c)=0.8907\]

Step 2 ：The standard normal distribution is a normal distribution with a mean of 0 and a standard deviation of 1. The question is asking for the value of $c$ such that the probability that $Z$ is greater than $c$ is 0.8907. This is equivalent to finding the z-score for the given probability.

Step 3 ：Since the standard normal distribution is symmetric about the mean, the probability that $Z$ is less than $c$ is 1 - 0.8907 = 0.1093. We can use the z-table to find the z-score corresponding to this probability.

Step 4 ：After looking up the z-score in the table, we find that $c = -1.23$

Step 5 ：Final Answer: The value of $c$ such that $P(Z>c)=0.8907$ is \(\boxed{-1.23}\)