What occurs when the direct sun rays hit a tropical line?

When the direct rays of the Sun hit the equator, it is either the Vernal (Spring) Equinox or the Autumnal Equinox, when there are 12 hours of sunlight and 12 hours of darkness in one 24 hour day. 

When the direct rays of the Sun hit the Tropic of Cancer it is the Summer Solstice in the Northern Hemisphere. The day of the year with the most sunlight hours in the Northern Hemisphere, and the least sunlight hours in the Southern Hemisphere. 

When the direct rays of the Sun hit the Tropic of Capricorn it is the Winter Solstice in the Northern Hemisphere. The day of the year with the least sunlight hours in the Northern Hemisphere, and the most sunlight hours in the Southern Hemisphere. 

In a right-angled triangle: 1- the hypotenuse is the longest side2- we can apply pythagorean rule which states that: (hypotenuse)^2 = (side1)^2 + (side2)^2for the given triangle,longest side is 15 cm  side1 = 9 cmside2 is 12 cm  to check whether the triangle is right-angled or not,compare (15)^2 to the summation of (9)^2 and (12)^in other words, compare 225 to the summation of 81 and 144if they are both equal, then the triangle is right-angles, otherwise, it is not.you haven't provided the diagram showing her work, so i cannot tell the choice. however, apply my explanation to the question you have.