To add these distances, they must share the same unit so first you need to first convert the swim distance from meters (m) to kilometers (km) before adding it to the bike and run distances which are already in km. To convert 400 meters to kilometers, divide the distance by 1000 to get 0.4km then add the remaining distances:

total distance = swim + bike + run
total distance = 0.4km + 20.8km + 4.3km
total distance = 25.5km

Calculate the number of vans needed by dividing the number of people that need transported by the capacity of one van:

vans = \( \frac{77}{15} \) = 5\(\frac{2}{15}\)

So, it will take 5 full vans and one partially full van to transport the entire team making a total of 6 vans.

The area of a circle is given by the formula A = πr² where r is the radius of the circle. The radius of a circle is its diameter divided by two so A = π(\( \frac{d}{2} \))². If the diameter of the logo increases by 50% the radius (and, consequently, the total area) increases by \( \frac{50\text{%}}{2} \) = 25%

To add or subtract terms with exponents, both the base and the exponent must be the same. In this case they are so add the coefficients and retain the base and exponent:

3c⁴ + 5c⁴
(3 + 5)c⁴
8c⁴

To multiply terms with radicals, multiply the coefficients and radicands separately:

9\( \sqrt{9} \) x 8\( \sqrt{4} \)
(9 x 8)\( \sqrt{9 \times 4} \)
72\( \sqrt{36} \)

Now we need to simplify the radical:

72\( \sqrt{36} \)
72\( \sqrt{6^2} \)
(72)(6)
432