This is moon orbit:Perigee 362.600 kms (356400–370400 kms)
Apogee 405.400 kms (404000–406700 kms)
Diameter of the moon is: 3.474 kms
This is the distance of the sun:average from Earth 149.600.000 kms
Nearest 147.000.000kms
Furthest 152.000.000 kms
Diameter of the sun is 1.392.000 kms
When the solar eclipse occurs, then the moon completely covers the sun and we see their shape as same.
If we see the shapes as same shape, the length ratios always same with diameter ratios.
But the moon orbit changing from 356.400 to 406.700 kms ( difference %14 )
And the earth orbit to sun is changing from 147.000.000 to 152.000.000 (difference %3)
Summing them we find %17 maximum difference of seems shapes .
If the moon at the nearest point and the sun is furtest point and if they are cover, then the opposite is impoossible. 17 percent are exposed to the sun.
With shape:
Precise and deadly