An inventor trying to build a better roller skate came up with what
breakthrough in transportation technology?

explanation:

select the correct answer from each drop-down menu.

different sources are aimed at different audiences. sometimes a source can be directed at more than a single group of usually aimed at the general population across the globe. some sources may have a very specific audience. be specifically aimed at students or scholars with a background in literature.

254.34

step-by-step explanation:

the formula for area of a circle is given by

a = pi * r^2

a = pi * 9^2

a = 81*pi

using 3.14 as an approximation for pi

a = 3.14*81

a = 254.34

the correct answer option is: weapons.

explanation:

tensions rose as the two opposing superpowers competed for 'weapons'.

referring to the cold war (1945-1991), the two superpowers, usa and ussr, experienced a phase of struggle and conflict with each other. these two superpowers considered each other as a threat to their survival and thus opted for policies to strengthen their positions.

the two superpowers never went to war with each other directly but competed for weapons to preserve their positions.

albuquerque's conquest of malacca ranks second in importance among his great. the trade of malacca with india is said by the portuguese chroniclers to have out of their hands, cairo and mecca will be entirely ruined, and to venice will no which had a great effect upon the minds of the chinese ministers