Determine whether the triangle is acute right obtuse or not a triangle 6,13,21

Really need on these. i have no idea what to do

Anyone know? will mark brainliest if correct

Write an introductory paragraph for this corrie ten boom and her family were faced with some difficult choices after hitler came to power. some family members paid the ultimate price. write a carefully thought-out paper of at least 200 words dealing with the following concepts: --how should a christian act when evil is in power? --what do you think it would be like to live in an occupied country? remember to proofread anything you write thoroughly.