HELPP 100 POINTS Each figure in the sequence shown is composed entirely of 1 x 1 shaded squares. If the pattern is continued, how many 1 x 1 shaded squares will there be altogether in the first 21 figures?

924

Shaded squares

Step-by-step explanation:

So we know that the pattern adds 4 new shaded squares every time, if we do that up to 21 you’ll get 84 for the last shaded square (21*4)

Now we want to know everything added up so we have to add 4,8,12,16,20...84

Theres a easier way then adding them 1 by 1

So we know the last number plus the first number is 88 (84+4), now this patter also repeats for the 2nd number and the 2nd to last number (80), so that is 8+80 which is also 88. Now we half the 21 which is 10.5, you then multiply 10.5*88 which is 924. You can use this method for any question but instead with different numbers.

-1/2 +2

step-by-step explanation: