Find the LCM (least common multiple) of the denominators, and use that as the denominator for the two fractions.
Ex.

LCM (3, 4) is 12

=
The slope of line D is also -4 because the lines are perpendicular.
Answer:
81 900 000 000 000 is 8.19 × 10¹³
Step-by-step explanation:
Write the first number 8.
Add a decimal point after it: 8.
Now count the number of digits after 8. There are 13 digits.
So, in standard form: 81 900 000 000 000 is 8.19 × 10¹³
C
Because 1 km is 1,000 meters so you were just multiply 1000 by 10 and get 10,000
c:
45 divided by 3= 15 then 15 times 4 =60 mph