#18).
-- The map has a scale factor of 1:25,000.
-- Any distance on the paper map represents
25,000 times that distance in the real world.
-- If you measure 6.8 cm on the paper map,
that represents a real distance of (25,000 times 6.8 cm).
#19). Relax, breathe, and take it one step at a time:
=> 7² = 49
=> 3³ = 27
=> (7² - 3³) = (49 - 27) = 22
=> 8 times that is 176 .
√121 = 11 .
Can you handle it from there ?