Select the proper placement for parentheses to speed up the addition for the expression 2 + 9 + 8 + 1 a. (1 + 2) + (9 + 8) b. (9 + 2) + (8 + 1) c. (8 + 2) + (9 + 1) d. (8 + 9) + (2 + 1)

The radius of the circle is 4 cm and the measure of the central angle is 90° the area of the sector with a central angle measuring 90° and radius of length 4 cm is vt cm the triangle in the sector is 4 cm the area of the triangle is v/cm² the area of the segment of the circle is (471 - ) cm?