"gcloud command not found" when run via crontab

So I installed the google cloud sdk by downloading the archive as follows:

$ wget https://dl.google.com/dl/cloudsdk/channels/rapid/downloads/google-cloud-sdk-225.0.0-linux-x86_64.tar.gz
$ tar -xvzf google-cloud-sdk-225.0.0-linux-x86_64.tar.gz

The above creates google-cloud-sdk directory with relavent files and I run install.sh which installs gcloud.

When I access gcloud from the shell, it behaves as expected. But when I try to access it via crontab, I get the error as stated in the title.

Any reason why could be the case??

P.S My intention is to use gcloud to perform firestore backups every 24hrs.

EDIT:
As Doug suggested, I referenced gcloud by its full path and was greeted with the following:

    Traceback (most recent call last):
  File "/home/ec2-user/google-cloud-sdk/lib/gcloud.py", line 95, in <module>
    main()
  File "/home/ec2-user/google-cloud-sdk/lib/gcloud.py", line 54, in main
    from googlecloudsdk.core.util import encoding
  File "/home/ec2-user/google-cloud-sdk/lib/googlecloudsdk/core/util/encoding.py", line 202
    for k, v in six.iteritems(env)}
      ^
SyntaxError: invalid syntax

I have set CLOUDSDK_PYTHON to /usr/bin/python2.7 (python 2.7.13) still the error persists. But the strange this is, this error doesn't happen when I run the command directly via the shell.

Answer: ok this is the behaviour of crontab which I wasn't aware of. It doesn't access the environment variables set. More info in this answer