Question: When did the state where KPHI is located become part of the U.S.?

full_context: Document 1: 51st state: Cuba, like many Spanish territories, wanted to break free from Spain. A pro-independence movement in Cuba was supported by the U.S., and Cuban guerrilla leaders wanted annexation to the United States, but Cuban revolutionary leader José Martí called for Cuban nationhood. When the U.S. battleship Maine sank in Havana Harbor, the U.S. blamed Spain and the Spanish–American War broke out in 1898. After the U.S. won, Spain relinquished claim of sovereignty over territories, including Cuba. The U.S. administered Cuba as a protectorate until 1902. Several decades later in 1959, the corrupt Cuban government of U.S.-backed Fulgencio Batista was overthrown by Fidel Castro. Castro installed a Marxist–Leninist government allied with the Soviet Union, which has been in power ever since.
Document 2: KORL-FM: KORL-FM is an American commercial radio station located in Waianae, Hawaii, broadcasting to the Honolulu, Hawaii area on 101.1 FM. KORL-FM airs an oldies music format. The station is currently owned by Hochman Hawaii Three, Inc.. It also transmits on Oceanic Time Warner Cable digital channel 883 for the entire state of Hawaii. Its studios are located in Downtown Honolulu, and its transmitter is located near Akupu, Hawaii.
Document 3: Honolulu: In 1845, Kamehameha III moved the permanent capital of the Hawaiian Kingdom from Lahaina on Maui to Honolulu. He and the kings that followed him transformed Honolulu into a modern capital, erecting buildings such as St. Andrew's Cathedral, ʻIolani Palace, and Ali ʻiōlani Hale. At the same time, Honolulu became the center of commerce in the islands, with descendants of American missionaries establishing major businesses in downtown Honolulu.
Document 4: Hawaiian Islands: The Hawaiian Islands (Hawaiian: Mokupuni o Hawai'i) are an archipelago of eight major islands, several atolls, numerous smaller islets, and seamounts in the North Pacific Ocean, extending some 1,500 miles (2,400 kilometers) from the island of Hawai ʻi in the south to northernmost Kure Atoll. Formerly the group was known to Europeans and Americans as the ``Sandwich Islands '', a name chosen by James Cook in honor of the then First Lord of the Admiralty John Montagu, 4th Earl of Sandwich. The contemporary name is derived from the name of the largest island, Hawaii Island.
Document 5: KPHI: KPHI (1130 AM) is a radio station located in Honolulu, Hawaii. The station, which is owned by Hochman-McCain Hawaii and offers a Hawaiian Oldies/Classic Hits format, and debuted between 2018-2019. In addition to broadcasting at 1130 kHz, it is also transmitting on Oceanic Time Warner Cable digital channel 882 for the entire state of Hawaii. Its studios are located in Downtown Honolulu, and its transmitter is located near Mililani, Hawaii.
Document 6: KKNE: KKNE (940 AM) is a radio station licensed to Waipahu, Hawaii and located in the Honolulu, Hawaii radio market, broadcasting with a power of 10,000 watts. The station's format is hybrid of traditional Hawaiian music and talk/information geared towards an audience adults of Native Hawaiian descent. The station is owned by SummitMedia. The station's studios are located in Downtown Honolulu and its transmitter is located near Kunia Camp. It is also featured on Oceanic Time Warner Cable digital channel 856 for the entire state of Hawaii. It was originally on 920 kHz and moved to 940 kHz in 1962.
Document 7: Hawaii: Hawaii (English: / həˈwaɪ. i, - ji, - ʔi / (listen) hə - WY - (y) ee; Hawaiian: Hawai ʻi (həˈvɐjʔi)) is the 50th and most recent state to have joined the United States of America, having received statehood on August 21, 1959. Hawaii is the only U.S. state located in Oceania and the only one composed entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean. Hawaii is the only U.S. state located outside North America.
Document 8: KIPH: KIPH (88.3 FM) is an American non-commercial educational radio station licensed to serve the community of Hāna, Hawaii. The station, established in April 2011, is owned and operated by Hawaii Public Radio, Inc.
Document 9: Overthrow of the Hawaiian Kingdom: The overthrow of the Kingdom of Hawaii began on January 17, 1893, with a coup d'état against Queen Liliuokalani on the island of Oahu by foreign residents residing in Honolulu, mostly United States citizens, and subjects of the Kingdom of Hawaii. They prevailed upon American minister John L. Stevens to call in the U.S. Marines to protect American interests, an action that effectively buttressed the rebellion. The revolutionaries established the Republic of Hawaii, but their ultimate goal was the annexation of the islands to the United States, which finally occurred in 1898.
Document 10: KTUH: It currently broadcasts on 90.1 MHz as of March 19, 2016 at 3:00 PM Hawaiian Standard Time. There is one translator at K217AA on 91.1 FM in the North Shore. In addition, it is also featured on Oceanic Time Warner Cable digital channel 866 for the entire state of Hawaii.
Document 11: KHWI: KHWI (92.1 FM), is a radio station in Holualoa, Hawaii broadcasting an Adult Top 40 format. Prior to October 2012, the station simulcasted co-owned KIPA and KHBC. The station is currently owned by Resonate Hawaii, LLC.
Document 12: KONI (FM): KONI (104.7 FM) is a radio station licensed to serve Lanai City, Hawaii. The station is owned by Hochman Hawaii Publishing, Inc. It airs an Oldies music format.
Document 13: 51st state: Before Alaska and Hawaii became states of the United States in 1959, the corresponding expression was ``the 49th state ''.
Document 14: History of Hawaii: The native population succumbed to disease brought by the Europeans (particularly smallpox), declining from 300,000 in the 1770s over 60,000 in the 1850s to 24,000 in 1920. Americans within the kingdom government rewrote the constitution, severely curtailing the power of King ``David ''Kalākaua, and disenfranchising the rights of most Native Hawaiians and Asian citizens to vote, through excessively high property and income requirements. This gave a sizeable advantage to plantation owners. Queen Liliuokalani attempted to restore royal powers in 1893, but was placed under house arrest by businessmen with help from the US military. Against the Queen's wishes, the Republic of Hawaii was formed for a short time. This government agreed on behalf of Hawaii to join the US in 1898 as the Territory of Hawaii. In 1959, the islands became the state of Hawaii of the United States.
Document 15: Hawaii: The Kingdom of Hawai ʻi was sovereign from 1810 until 1893 when the monarchy was overthrown by resident American and European capitalists and landholders. Hawaii was an independent republic from 1894 until August 12, 1898, when it officially became a territory of the United States. Hawaii was admitted as a U.S. state on August 21, 1959.
ground_truth: August 12, 1898
sub_queries: In which state is KPHI located? Answer: Hawaii
when did Hawaii become a part of the united states Answer: August 12, 1898