If the first 100 elements on the periodic table, 13/100 were discovered in the ancient times, and 21/100 were discovered in the Middle Ages. Another 5/10 were discovered in the 1800s. What fraction of the first 100 elements was discovered after the 1800s? Explain.

, 61/100

Step-by-step explanation:

First we need to add all of the fractions before or at the 1980s, they have the same denominator, so we simply just add. It comes out to 39/100. Subtract 39 from 100 and we get 61 out of 100 or 61/100 or 61%.

just take the area of the square and then the area of the circle then subtract the circle area from the squares area

step-by-step explanation: