The others are right that you were missing a colon at the end of line 1, but you also have another problem:
input cannot be used as a variable name as it is a reserved function name. You can change lines 5-9 to this:
base = float(input("enter base: ")) height = float(input("enter height:"))
and it should then work.
next time try reading the er. You can see the
invalid syntax at line 1 of the script.
You are missing a colon.
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