altitude of the top of the hill = -77 feet
Explanation:
check point 3 = -217 feet
Top of hill is 140 feet above check point 3. This means we would add the distance above the check point 3 and check point 3 to get the distance or altitude to the top of the hill
altitude of the top of the hill = 140 feet + (-217) feet
Multiplication of same sign gives positive number. Multiplication of opposite signs give negative number.
There is a positive and negative sign (opposite signs). This means the result will be negative
altitude of the top of the hill = 140 feet - 217 feet
altitude of the top of the hill = -77 feet
