You count how many across the parallelogram is (which is 4) and you count how high it is (which is 5). Then you multiply 5×4* which equals 20 square units.
*The reason you do this is because base×hieght=area
During the period 1994 - 2004, the 'National Income' ,(NI) of Australia grew about 5.2% per year (measured in 2003 U. S, dollars). In 1994 , the NI of Australia was $ 4 billion.
Now,
(2020 - 1994) = 26
Assuming this rate of growth continues, the NI of Australia in the year 2020 (in billion dollars) will be,