How to find a and b? (pascal's triangle)

The two 5005s tell us we're in the middle of Pascal's triangle, which has bilateral symmetry.

So we can add the a and b labels to two other points by the symmetry as shown.

The two equations we can write are then

5005 + a = b

a + a = 12870

a = 12870/2 = 6435

b = 5005 + 6535 = 11540

a=6435, b=11540

Check:

Those are right, they happen to be

a. the residual plot for model 1 has a random pattern and is a good fit for the data.

1) c 2143.6 cm

2) c 113.0 m

3) a 33.5 ft

4)   d 2 cm

5) c 20 mm

6) 180 in

7) d 120 ft